I understand this very much, but - I want to say this as gently as possible -
it’s not his to work on. It’s yours.
we can’t control other people.
if his compliments trigger you, a therapist can help. But lacking a therapist: separate what is inner story you’re creating from what is actual fact.
for example. Fact: he said “you look beautiful tonight.”
story: “that means all he cares about is looks / all men care about is looks” spiraling into “couldn’t get dates/ he wouldn’t have even glanced at me before I lost the weight.” etc.
these stories are going to make you feel so shitty - and they’re not true. They may have a basis in your past experience, but they’re stories now.
a therapist could dig down to what is hiding underneath all this - perhaps fear that you’re not loved for you.
truth is. Yes, looks attract someone at first, but that is not what keeps people together. That he still notices and compliments your beauty is wonderful - because often times people just get used to each other, and noticing when a partner looks good just falls by the wayside.
relationship is all the rest that connects you- the looks thing is just a bit of icing on top. Enjoy the icing , and I hope you heal enough to allow yourself to simply receive. Receive a compliment , take it in, you are worth kind words and you deserve them.
if you need to, translate them. Do your own mantras of “I am strong” - whatever words you need. Those things don’t need to come from someone else , you’ve got your own back and you always have done.