Friendship as an adult can be hard. Hard to make but also to sustain. It’s not so much that having a spouse or kids and whatever else really changes you, but it does change what you have time for. First of all, different people react differently when a new person enters their life so don’t be too quick to judge. I think that’s what messes us up, it can even just happen when a friend makes a career move. Its easy to say, “they’ve changed and they’re what not my friend anymore.”
What we often don’t think of is that friendship is work, any relationship is work after all, but when it’s more work than fun that becomes a problem. But it’s not a problem you need to resolve, not always anyway.
So don’t overthink it. Don’t blame the other person because you’re probably just as much to blame. Don’t suffocate someone, just stop trying so hard. A true friend will be there when you need them, and when you need them you’ll know they’re a good friend.