Do you think he is wanting to get out of child support?

I honestly don't know... Part of me thinks it's wrong, that it's grown up discussion... on the other hand though.. he is the dad and maybe he is wanting his son to live with him (just as you want him to live with you as well) and he thought he would ask to see how he feels about it.. I don't know...

My XH did this to BS when he was around 11-12. I called XH out on it immediately. XH denied it but I had heard about it from three difference sources and none of them ever communicated amongst themselves. After I called XH out on it, it never happened again.
No reason to put an 8 yr old through that pressure.
I wouldn't tell your BS to reply to him, I would call him myself and say...NOT UP FOR DISCUSSION and leave it at that.

You tell DS the following….”A judge ordered that you live with me until you are 18. You WILL live with me until you are 18. No if ands or buts about it. I am not sure why your dad is asking you that but it is not for you to worry about since it is in the CO. Tell your dad to talk to me next time he says something like. You are a child and should not be in that type of conversation. ”

DH is guilty of doing this to both skids. Because he thinks BMs are scum (which they are in our case) he was always putting the bug in their ear about living with him... although I suspect this NEVER happened, until I came along... not that I'm so special but we all know how a lot of these men are in that they want their GF/wife to do all the work, while they get the glory.

How long has he been with GF? I wonder if that is the sudden interest? I feel bad for your son. Not fair for an 8 year old to be put on the spot like that.

My Whiskey Tango ex-husband did this to my son, when he wasn't even seeing the child he had with the woman he left me for. Anyways, at 8 I didn't say much to my son except that he is living with me. As for the ex, I know you can't argue with stupid so I didn't allow myself to get drawn into his drama. I just let it lie. If it comes up again, maybe say something then. For now just worry about your son and how he feels about the situation.

The BM in our life will TELL the skids she is going to get custody of them. Tell them all the things her current BF is going to buy them once they live there. Rainbow and butterfly promises to fill their little heads. She has once actually tried and the judge about laughed her out of court. She only gets supervised visits every other Sunday.
One of her exes even stated she only wanted to have kids because she would get money from DH. She said that to her BF. WTH?
There may be NCP that want their children with them but for the most part I feel like it's just a money grubbing scheme or a way to hurt CP.

BM is trying to do this now with SS4; she's telling DH that she's having trouble physically getting him to come back home but when she pulls in the driveway he always runs up to DH and is quite cheerful. There hasn't been any tears since he was 8months old. DH has had to tell SS to go to BMs car before but DH never brought it up because he could tell how hurt and angry she was when it happened. She complains that it's getting harder for her to explain to him why he can't stay with her, and like I told DH, I will tell you: there is nothing to talk about! Mommy and Daddy live apart so a judge who makes all the rules decided where you will be and who you will be there with until you are legally an adult. I think you could email your Ex a reminder that any schedule and or custody changes aren't to be discussed with the children as they have no say in the matter. If I were you I would also include what your son told you: he doesn't want to go live with his dad, but he didn't want to hurt his feelings. Sure your ex might say something to your son about talking to you about it but your Ex had to know your son was going to talk to you about it, he'll just be mad it was to say he was uncomfortable with the question and not "I want to go live with dad". It's really disgusting when adults pull young children into things like this.

I see where you are coming from, I have a 9 y/o with my abusive ex, and he played nice and did the "work" so he got his unsupervised visits. Good, now we have a CO saying what your visitation is. He, somehow, has the idea that for every year that goes by, he should be entitled to more parenting time. He is not above threats and coercion and/or trying to involve our child in adult conversations. I WANT my daughter to have a relationship with her father, as long as I have no indication that she is being harmed. I do believe that she loves him, and he loves her. I do, however NEED the court order to follow, or it is a boundariless free for all, where I am threatened when I do not agree to give him his way. I do avoid talking about court and other "adult" things when at all possible, and try my best to keep her out of the adult discussions. No parent should just go to a child and put that kind of pressure of them, especially without having a conversation with the other party. Eight is very young to put that question out there, and in most states, your son verbally saying he wanted to live with his dad wouldn't be enough to change your current agreement.
I also see your point that court orders are not meant to be continually modified or brought up for change all the time, court is stressful for families and children. When dealing with an ex who has been abusive, regardless of whether that person abused the kids, I feel that a CO is essential, because many abusers will use any wiggle room or freedom to their advantage, or to exploit the victim, even if they have completed all the classes and programs.
That being said, this is probably the wrong crowd to gain any sympathy for your plight. Many of the members here are used to dealing with BM dicking their DH around for custody, visitation, and child support, and assume that you are doing the same thing. It's pretty easy to just throw that blanket over you, especially when many people here are not talking about their non-step issues, and they have no idea what your personal situation is. I suppose if I didn't have the perspective of having lived on both sides of the situation, it would be easy for me to do that, also. Just my opinion/experience.