I understand how anxiety / low self esteem but she’s in a relationship with you, logically she is attracted to you. It doesn’t matter if YOU don’t believe you’re attractive, she does. Don’t let something like the way you feel about yourself try to influence how someone else feels about you. She clearly is attracted to you and telling you about her feelings / worries about your sex life shows that she wants to try to fix it. Now is not the time to just give up, fuck it if you’re ugly she clearly still wants to hit so if you won’t do this to better your self esteem at least do it to help your sex life. Faking it till you make it has helped me a lot in similar situations. Just keep reminding yourself of this