Comfortable sex?

I’m almost 30 weeks and the fiancé has been wanting to get some action in but it’s super hard for me cause the positions we’ve tried have made me hurt afterwards and/or just aren’t comfortable or pleasing for me on my end and I can tell he’s getting frustrated not being able to have sex. And he’s afraid to hurt me or throw me into early labor or anything. This is our first kid so we are new to the whole pregnancy life and what not. Any suggestions on what we can do or try? What positions are the least uncomfortable for you??