Option 1:

Lay out for him exactly what you need when he has the kids eg. you want to stay over on Wednesday night, you want phone calls on Monday and Friday and you want at least 2 daily texts. Plus you want the option to hang out with them on Saturday. 
Explain that these things will help you feel less like a mistress who he sees when he isn't with his family and more a partner in his life. Point out again (I presume you already have)  to him that though you don't want to live with his kids you don't mind spending time with them. 
Then sit back and see how/if he tries to integrate these needs into his life. His willingness to adapt to your needs will tell you if this is worth sticking around with him. 

option 2: 

Reallize that sometimes love isn't enough and that the practical aspects of our lives have to align too in order for a relationship to work. I know that you can find another love once you let go of this one. 

You say you have good communication in this relationship.  However, despite you telling your BF several times that you find it hard he never even phones you on his kids' weeks - he doesn't seem to have taken this on board. If I was in a relationship like yours - a call, 2 or 3 times a week would be the absolute minimum for me.  If he truly had respect for you - he would consider your needs alongside those of him and his children.  You do not disappear into the ether on his kids' weeks - you are still a person who can feel lonely, neglected and second best. 

Does your BF know how angry you feel?  If not, I suggest a come-to-Jesus meeting to let him know how serious the situation is for you and that you may not want to sustain the relationship unless he starts actually valuing you as a person and not just as his squeeze every other week. 

It sounds like he is completely overwhelmed by having 4 kids on his own during his weeks, and doesn't have the bandwidth for anything else. Whether that is by his choosing (kids are my whole life and come first above all else!) or just something he struggles with, remains to be seen. It's unfortunate that you have tried to communicate your needs and he still is not meeting them. If I were you, I would do what was suggested above- tell him that for you to be happy in a relationship, you NEED to have communication each week, even daily, and can't feel abandoned. If you clearly state your needs and he still does not adjust to meet them, unfortunately you have your answer. He is either incapable, or unwilling, to try to make sure you are taken care of, as well as his kids. And trust us when we say that it is a crappy place to be, competing for attention with kids when a man doesn't understand how to balance it or that the adult relationship should be the priority after the kids needs. You will never be happy being a second thought, fighting for attention. 

And for the record, I completely understand about needy, clingy kids when that is not how I was when I was young. SD14 (less these days, thankfully) was constantly asking DH to play games and entertain her. I'm just like, you are 14 girl, why on earth do you want to play UNO every freaking day?! Her clingyness was very strange and seemed immature to me, as everyone I knew at that age was out doing their own thing. I try to remember each kid is different, but it is definitely hard when they are the complete opposite of how you were as a child. 

First of all, even if you did have kids/want kids/enjoy kids, the fact that he ignores you 50% of the time is a big deal. Do you even know how he spends his time during those weeks? After 3 years, that's pretty weird.

Also, as great as he is half the time, does that outweigh the other half the time? It doesn't seem like a child-free by choice person would thrive in this situation. The youngest is 4 years old and there are 3 (three!) more. Have you spent much time around these kids? Do you know how he functions as a parent, 3 years in? For all you know, they could be poorly parented little terrors. Are they even kids you would want to spend half your life with?

If you really want to try to make this work, you could try counseling. But think about this. Even though this guy is 100% what you want, it's only half the time. What if you found a child-free guy who is 80% of what you want, 100% of the time? Or if you are older, a guy with grown or near-grown kids who were parented well and aren't burdens into adulthood? You really don't know much about the other half of THIS guy's life and you have been with him 3 years. It might be bad.

Also, if you do stay with him and start seeing him the other half, you will be a child free person with 4 stepkids. Even half the time, that is MUCH worse than having 4 kids of your own. 

Honestly, I'd be inclined to find a new boyfriend.  If you're feeling like a half time girlfriend, your BF isn't ready for your relationship.  Also, you've communicated your needs and he hasn't made the effort to try to satisfy them.  Move on and find someone for whom you can be a priority. 

He is not able to meet your needs. I also don't think there is any stability in the long run. I would not want to be in a relationship when I knew we could never move forward. Moving in together isn't an option. It's YEARS before all of them age out. I personally wouldn't want to be a part-time girlfriend either. Convenient for him though!

Find an equal partner that is childless and WANTS to spend their life (full-time) with someone. 

So, whatcha gonna do about it?

Hmmmmm?

If he actually loved you he would not treat you like his side piece/back door girl most of the time and subjigate you to his failed family baggage.

As for "such good communication in a relationship before this". Read your OP. A big part of the struggle you describe is that he goes completely communication silent when his kids are with him.

Please do not continue to sacrifice yourself on the alter of SParental martyrdom to this failed man, failed father, failed mate, failed adult, and failed partner and his failed family baggage.

Get on with your life.  Live well.

Living well is what we owe ourselves. It is also the best revenge.  Enjoy living your revenge... well.

You will find a true quality partner. When you are living well and are happy, that person will appear in your life.  So quit picking shit with the chickens and start soaring like an Eagle!!!!

Lana,

Welcome by the way. I hope that you find this to be a good place to vent, contribute, and to pick up some useful perspective from others who are living the dream of the blended family adventure.

Deep breaths and take care of you.

He's the most fun person you've ever been with..................so far. That isn't enough to build your life with someone.

If he respects you, he would respect your feelings.

If living together and consistent communication are important to you, he's shown you he's not a good fit for you.

What you want/need is not wrong. Forcing a square peg into a round hole is wrong and very difficult.

I am in love with a man who I've been seeing for 4.5 years. We've toyed with the idea of marriage and lived together for 18 months. It was lovely. But ever since his mom died, his worse traits (poor communication, poor conflict resolution and selfishness) have intensified. He seems to struggle with showing empathy and care.

I love him and he is someone who is wonderful! I mean, when things are good, he's golden. But he's moody and when things are not good, he tends to distance and shut down.

I love him dearly, but I already have a circle of friends and family who are WARM, loving and empathetic people. If they saw me hurting, they would come to me to comfort me, call me, check in on me. They would listen to my concerns and try to reassure me. He's not so good at this and if the issue is about us, he tends to dismiss my POV and feelings.

Love is not enough.

I can't keep investing my time in a person who doesn't want to build a life with me and be someone I can trust with my feelings or who will commit to doing life with me.

Sometimes you have to walk away from someone you love to find someone you can do life with.

I think we are very close to ending our relationship. It will be sad, but I know after 57 years on this planet that life goes on. The tears dry up. You find your joy again. And, maybe, if the stars align, you get another chance at love. I've had a few, but my man picker is broken, so I think I will take a couple of years off to fix my picker. ((hugs))

He may feel that he's a family .  That you don't want to be part of that family. Like taking some of the child care load off of him. He may be upset at you.  Because he wants you to do for his kids  so he will have time for you.,,

'What ever, the youngest is 4 yo. This is not going away . Not for 16 years.   You must decide what you actually want out of life.  And tell him.  See what he actually want out of his life.  Then work on it or make an exit plan. This could not be the type of relationship you want. He will be taking his kids on vacation , are you going ?  Do you want to go to Disney for a week with 4 kids ?  

I would not be exclusive with a man who could only give me half his time at best. 

He has 4 children. You want none. This is your life for a minimum of 14 years. Is he worth living a half-life for 14 years or more? It seems to me you are completely incompatable. You need to decide what you want out of life and make some decisions. You deserve better. 

Find a new man hun

You said you have no desire to be a parent

He has 4 kids that will always be his kids

He cant seem to juggle 4 kids and a GF

He expects you to be there every other week.

Nope, move on.

Love aint enough

you deserve a fulltime BF

Blessings