am I wrong?

I found a semi nudey pic of a girl my boyfriend & I went to school with saved in his phone. she uploaded it to Facebook & he saved it from there. I'm nearly 30 weeks pregnant. we were still having sex, he feels me up, says he's attracted to me this & that BUT since I found the picture i feel like he fantasizes about her while we're doing it & I haven't wanted to have sex since, or go out in public really. she's a really thin fit girl & I'm not in horrible shape, just pregnant with a little extra thigh weight lol. idk if it's hormonal insecurities but... my sex drive is still high BUT I don't wanna have sex when the whole time I'm going to be wondering if he's thinking of her 😭😭