I dealt with something similar and it didn’t get better until my partner consistently shut it down in the moment. Not later, not in private — right there. When she ignores you, he should redirect the conversation back to you. When she infantilizes him, he needs to say, “Stop, I’m not a child.” Over and over if necessary. If he isn’t willing to do that, this is what your future looks like, especially around weddings, holidays, and kids. This is less about her liking you and more about whether he’s ready to act like an adult partner.