feel like im nott good enough for him

So ive struggled with depression for 6-7 years now and im just having one of those days where all the bad thoughts are racing through my head and i just feel like im not good enough for my fiancé. We've been together for 5 years and he helped me beat selfharm and helped me get better and stayed through everything. I just feel like he could have someone prettier than me, smarter than me, skinnier than me, someone who doesnt have depression like me. And the thing about is, is its all me thinking this. He doesnt treat in any way that would put these thoughts in my head. Can someone give me some advice? Sorry for the length