I've convinced myself my boyfriend dosn't love me.

Ok so i have the most amazing boyfriend he is honestly everything i ever wanted he is never mean to me he hates to argure he is just a really sweet guy. Here lately i have been feeling really down i dont think i'm very pretty and my boyfriend is tottally hot and i'm scared that im not hot enough or somthing for him and he is just going to leave me for the next best thing but he keeps reassuring me he wont and we've been together 4 almost 2years. I have also been having these issues i keep thinking that if i look at something or think something or touch something the wrong way that he is going to be with one of his ex Girlfriends and i keep having these gross sexual images run through my head of him being with them and it really pisses me off and i almost get mad at him but its in the past it was before me and i love him so much so y does it keep bothering me so bad ive been trying for months to get past this please give me any advice i'll take it. Also i keep thinking if i look at or say or do something that might be offensive or something that may be offendingg GOD then he will put My boyfriend with one of his exes or with someone else but me because i don't deserve him and when i think about all this its gets me really upset and fustrated and i feel like or have these thoughts that i am mad a God nut i'm soooo NOT it just feels that way or like i am blaming him for how i feel or all the crap i think but i feel like its my OCD and its something maybe he wants me to overcome and deal with instead of always asking for reassurance and taking the easy way out.

Thanks so much for reading all of this and agian any advice or anything is much apprciated love u all!!!!!