sex problems..

So I was having sex with my boyfriend and he kept like... Cringing like he was in pain or something and totally wasn't into it. I am 34 weeks pregnant and sex is a little more awkward now haha so I feel like I was hurting him somehow?? And after like his 10th time flinching i asked him if he was okay and said it seemed like I was hurting him and he got awkward and said no he just came already.. But he hadn't haha when I cleaned up after there's no cum.. he lied about Cumming? It just felt so awkward and now I feel bad for making it awkward because I think he's embarrassed- but I don't get it, if I hurt him why didn't he say so and why did he lie about cumming?