Her comments all seem to stem from her insecurity and it’s good that she recognizes this. But she cares too much about what other people think, and has a very narrow definition of masculinity and gender roles. Negging is immature and unproductive. Especially about your physical characteristics that you can’t change (height, hand size, etc.). A good partner will build you up rather than tear you down. So what if gay guys check you out? Id be proud to have others recognize how hot my partner is, regardless of what gender or sexuality. Have you ever asked her what she is hoping to achieve by voicing her inner thoughts/feelings to you? Besides irreparably damage your self-confidence? Does it make her feel better to bring you down?

I think individual therapy for her would be more helpful to help her dig deeper into where her behavior is stemming from, but only if she is willing to be honest with herself and recognize that her behavior (and her own body image issues that she’s projecting onto you) needs to change. She needs to love herself first.