With much love... why are you asking us?
Ask your husband.
It sounds to me like he'd prefer to have his bed back to just the two of you but understands entirely why, for lots of reasons, things are the way they are.
He sounds supportive.
I co-slept with my son until he was 6. I'm a huge advocate of co-sleeping, I don't think either of your children 'should' be in their own room - unless your marriage is really suffering. But if everyone is happy and getting sleep, that's a win for me. Even if your babies are easy. Because the bonds you're building are magical, and your husband is right - you won't get the time back.
The only way you can find out if your husband is accurately reflecting his real thoughts and feelings on the situation, is by having an open and honest conversation.
Doesn't matter what your mil thinks, or your friends, or us randoms on the internet.
If you are all happy, stay happy.
If one of you isn't, what compromises need to be made?
You sound really anxious and still quite low. Take care and don't let other people create unhelpful narratives in your head. Talk to your husband x