Frustrating sex...

So hubby and I just got married. I was a virgin so sex was super great at first. My husband has a gut (sorry for lack of terms, I love him so much lol) and  it's so frustrating because I have to move it so I can insert lmao. We've been on this diet so much that it's laughable to say that... He won't stick to it and I try. He has lost a little weight before but senior year of college came and he stress eats, which I understand. I need help to try and tell him it's frustrating during sex. I don't want to hurt his feelings. 😔🙃