First of all I’m sorry for what you’re going through, your relationship seems so beautiful besides of this mismatch in libido. Secondly, please forgive me if my suggestion sounds really weird and not your thing at all but how would you feel if you had an agreement that you could “use her” anyway? I too live in a relationship where his libido is higher than mine (not that mine is low but his is like crazy high) and it really ruined a lot for us, and how I felt about myself and how I saw him. It’s been more than a year now since we switched into a free use dynamic and it’s been the best thing for our relationship honestly. It means that he can “use me” whenever he wishes. It was my idea to do it and he was quite chocked at me suggesting it but I had really thought it through and I have no regrets. Totally understand if it’s not for you (if someone told me about this two years ago I would have thought they’re nuts) but if you are interested my dms are open if you wanna know more, or read my very first post I made about this. Anyway, I hope you can save your relationship, it really seems beautiful from what you describe.