Most Helpful Girl
I have/ had the same problem, but I've found that by vocalizing positive things about yourself-- like looking in the mirror and saying "You are strong, you are beautiful, you are you are loved," etc.-- enough times and forcing yourself to act like you believe it eventually leads to you actually believing it. By vocalizing these thoughts you make them more concrete and therefore more tangible. You could also try writing them down and saying them aloud.
Most Helpful Guy
this makes me sad bro this makes me sad. i wrote a take about this a while back i won't link it here as that's annoying in my opinion however you have to put it on her because it really is her with the problem undermining you trying to get you to question your looks your value to her and to women in general. don't take responsibility for that and don't feel other women feel the same way but be aware that some other women do that as well. find you a nice girl and learn to trust again.