I can't have sex ! HELLLPP

So I'm 15 weeks 4 days pregnant and lately when my bf and I have sex I feel so uncomfortable I tell him to stop. I cried and apologized a million times to him and he just hugs and kisses me and tells me that's it's ok he and that he loves me regardless if we have sex or not but I just can't help but feel horrible. We already have little sex (2x a week if that) idk what to do, any advise!?!