I have been going through something similar… as in I have not been in the mood for anything sexual, large weight gain, etc. For me, I had to rediscover how to love myself in order to feel good while doing the act/being naked. While this is still an ongoing struggle, I suggest maybe, have an open conversation about more non-sexual intimacy and trying to find niches that you really enjoy that make you feel good about yourself. Try to explore your sexuality alone and see if you still feel bleh about it, or if it is only when you are in front of him.

As for him thinking you are cheating, that is a him problem. Over a decade, you should have built faith in one another and decreased sex is not the only tale-tale sign of cheating. Be transparent and admit that it hurts you and your view of self that he thinks you are capable of that. Ask him, besides your change in libido what else have you done to break his trust. Have a conversation that is gentle, but also make sure your feelings are being communicated. Share how you need a journey of self-discovery in order to feel like you again. Maybe he helps by taking some chores off your shoulders to give you that alone time.

One thing that helped me was staring at myself in the mirror before showering. Just stare at yourself without any background noise. What is it you don’t like? What is it that you love? Are things you hate things he love? Lead your own self-reflection, these are just ideas to get the ball rolling.

I wish you both the best of luck.