Is there a reason why he still is not legally separated after 3.5 years??

If you read, you'll find this is not uncommon for jealous BMs. Your boyfriend needs to handle things legally. And this is HIS battle to fight. You cannot care more than the parents.

This divorce thing between your gentleman friend and his still wife, could drag on for years. And Canada has different process than we do in the states. If she is giving him this hard of a time merely agreeing on a parenting plan, she isn't going to let him out of any of this any time soon. 

And you sound like such a sweet lady. Very likely one that would be a positive one on the two boys... which is probably why the mother of these boys dislikes your presence so much. You sound like everything she is not and will never be. 

I would be sure to keep your present home and not attempt to move in with him nor move him in with you. He has far too much 'business' yet to tend to before you'd take your relationship any farther. Date him, enjoy his company, keep being kind to the boys who likely need positive attention and activities, but keep yourself ready and willing to move on. You found him, you'll have no problems eventually finding another worthy of your affection. Meaning, don't sacrifice for this man. You don't need years and years of a crazy wife, hopeful ex-wife cluttering up your peace of mind and sense of well being. 

You've raised your two children and you're currently in a different stage in life than your gentleman is. Even if he is trying to get out of his current marriage (and so far failing) , he is not free and able to live the life stage with you that you deserve. Just be sure you don't allow him to hold you back from enjoying life while you get put on stand-by. 

With the wife now claiming accusations (even  though you know the claims are false) these things can really damage reputations and put huge divisions between father and children. And though, I'll never understand child support in Canada, he may also be on the hook for financially supporting his children way up on into their adult years and with "special needs" adult children, perhaps moreso. Be sure to keep your own finances to yourself, don't be tempted to open your wallet and bail your gentleman or his children out of financial difficulties. This man could end up having to not only support his children (as he should meet his responsibilities to them) , but also his obese crazy still wife. 

Really the only thing he can do is get a lawyer and press for a hearing to finalize the divorce. Dating a man who doesn't have this stuff handled after years is very frustrating- believe me!! My husbands divorce took 5 years to settle and we still barely have a custody agreement. Don't move in together until that divorce is finalized. That can wind up really messing him up when it comes to alimony. Once he is officially divorced and there is a custody agreement he can start getting her for contempt and for disparaging the other parent, but until then, he has nothing to stand on. 

It's jealousy pure and simple.

BM told the skids I:

1. Put my body spray on wrong (I still can't get over this... LMAO... I odn't even know how she would know how I put it on or how you can put on BODY SPRAY wrong. LOL)
2. She rives better because she lets them have the lights on in the car at night when she drives. (LMAO, says the woman who has lots of HER accident crashes and speeding tickets vs. my perfect driving record, but okay.)
3. OH also, I'll never be anyone's real mother. (coming from the woman who ditches them moths, to weeks, to a year at a time.... Cuz she sure is the STEALLAR example. LOL)

She's jealous and being petty. Just never stoop to her level. Make sure your SO finalizes the divorce prior to moving in and he goes for contempt. Once there's a plan in place. DON'T DEVIATE.

In addition to what everyone has wrote above. Kids who are considered disabled or unable to support themselves because of x disability may qualify for life long child support. They do here in the states.

This is a topic so few people talk about here and everywhere else. Kids today are soooo highly labled with 'something' it seems almost like a serious crisis that keeps growing and growing.  I suspect we have not seen the gravity of this 'crisis' and wont until the 30 and 40 year old parents kids reach emancipation age.

Be smart about this guy. Truthfully long term does NOT sound like a swift idea. Already way to much junk to deal with and he is not divorced. HUGE problems ahead.

JMO

NOW back to his wife not giving contact.

They are married. She doesnt have to do anything. If dad wants contact he should go home and see his kids. IF He want seriously wants out of his marriage he should file for divorce. Forget the parenting plan...heck it will be months until a court date. On top of first hearing....add on a year or two until a reasonable custody order is

I would not go one step further with him until he files the paper work. Lets face it this man is not available and has not for a few years. Sounds like he is pulling your chains. So sorry.

JMO

GoodLuck