Perhaps your wife has some emotional pain that is causing her to disconnect from herself, and thus be unable to connect to your love for her. That could cause some desperate pushing away, and disconnected occasional sexual encounters. Deep emotional pain.

I agree with others that your wife needs to own that she has a problem, but you may need to learn about the depth of lived emotional experience also . It is hard to build bridges across deep experiences of pain, no matter what the reason for them. It's a hard learning .

It does sound like your wife has tried to communicate with you about how she feels about her weight gain, and that it's not an answer for you to tell her that you feel ok about that. She has "lost control" of her body weight. Searching for a kind supportive way through this, I wonder if there is anyone she can trust to support how she feels right now? A friend? A family member? You also deserve support.

These are just my intuitive reactions from my own lived experience. Bridging into relationships when suffering inner pain is difficult/ impossible - and however loving/ particularly loving those relationships are can appear like a pressure.

I do think you can find a way through this - IF you both have a commitment and compassion. Not to deny your sexual feelings, but also to be open to learning about each other's emotional reality.

Good luck!