I agree that it's annoying, OP, but you can't control other people's thoughts about you, no matter how wrong they are. It sounds like you and your husband are doing what you can by communicating clearly and sticking to your boundaries.

The only other thing to try is for all communications to go through your husband, and then he doesn't tell you what they say. My MIL use to drive me crazy (she's critical and controlling) and I gradually dropped almost all communication with her. I'm sure she has uncharitable thoughts about me, but now I don't have to hear them so I don't care.

Think about it this way. It IS because of you.

You and your child are the motivator your husband needed to assert boundaries between himself and his parents If he wanted to buy their house, marrying you wouldn't have changed his mind about that. If he really thought going there on Christmas was important, he would have gone regardless of what you wanted or didn't want.

It was probably a pretty big deal for your husband to get to be his own person. You don't sound controlling, and it is reasonable, what he has asked. They have to blame someone. They are blaming the person NOT part of the enmeshment, rather than the person who wants to leave it. It's easier for them this way.

Remember that your husband has your back and you are both achieving a successful and gradual distancing - so lots of things to celebrate here!

It's understandable that your husband's mentally ill parents would accuse you of taking away their son - I mean, it's true, to a certain extent, and thank goodness you're doing it
So try to ignore their whining as much as possible, especially if your husband defends you, which is the most important thing for your marriage.

They are unsettled at what they perceive as your DH slipping out of their grasp. When they say jump he no longer asks how high. You’re the easiest target they can lash out at. Since your DH is in your corner you have a major advantage right there. He’s doing it right, so let him handle his parents. FIL can learn to deal.
Continue to be cordial to your in-laws. Don’t badmouth them to your DH.

Move away asap that will help enormously

I feel you OP. I really do. I've been there! You're a scapegoat and they need one in order to process the reality that their son has his own family and needs to prioritize them. Their family dynamic has changed forever and they are grieving that. Unfortunately, they're not emotionally equipped to deal with it in a particularly adult way and you'll just have to stand your ground and accept that they may always act this way.

It sounds like you and your husband have set boundaries, which is incredibly healthy. As long as you and your husband are on the same page, you'll be fine. Obviously there are benefits to keeping a decent relationship with his parents for both your husband and son but it's okay if you're not super close with them. It's exhausting. I'd love a warm, loving relationship with my in-laws but it's not in the cards and I just take what they can give (and stay close to my husband's other extended family who I love very much). I really hope they come to terms with things and can feel happiness for you and your family some day. Take care!

My DH and FIL go on 2-3 day fishing trips a few times a year. My husband recently changed jobs and works out of state for 6 months of the year. He was home for the month of December. My FIL planned a fishing trip without asking my husband about dates and he could not go because we already had plans. My FIL then tried to plan a fishing trip on my birthday weekend and also the week before my husband leaves again. I had taken a week of vacation time to spend with my husband and son and my FIL wanted to take my husband fishing during this time. My husband told his Dad no, and that he needs more notice and to be consulted on dates before my FIL plans the trips and takes time off.

The other issue is that my FIL recently had COVID and there are unvaccinated family members. DH and I chose to stay home on Christmas this year and not visit, my FIL was PISSED about this. My MIL called me on my birthday to ask me why we weren’t coming to their house on Christmas. DH did not want to go and expose us or our son and risk getting COVID a week before my husband and leaves. My FIL and MIL both said to my husband on the phone they feel like he "can’t do the things he wants to do" which DH strongly refuted and said he doesn’t want to get sick, get his family sick, nor does he want to go fishing on certain dates because we already have plans as a family.

DH and his family used to have a very enmeshed dynamic. My FIL thought we were going to buy his house from him and have them still remain in the home. My DH used to live at home until he was 30. He and his Dad were very close but we now have a toddler and a life of our own and are planning on moving away. DH is planning on going over to his Dads house but I am PISSED that I am somehow the common denominator or that’s my FIL’s perception that I am somehow to blame when it’s his own lack of planning and not wanting to risk getting COVID or continue their weird enmeshed dynamic and LIVE with them in their house.

I’ve had no part in DH’s decision to not go fishing or not go to Christmas. I don’t care either way. I’m not close with my IL’s at all and it’s clear that their perception of me is dependent on how often I play along and show up to their house.

I’m really just venting. I’m glad DH sticks up for my but the comment FIL and MIL made really bother me.