Painful sex while pregnant

Currently 32 wks pregnant as of tomorrow. In the last 5 months me and my Bf have only had sex 4 times because every time we do it starts to hurt and then burn, to the point I’ll be in pain for a day or two afterwards. Before that it didn’t hurt at all, there was a time for a month we didn’t have sex because I wasn’t feeling it then we went to have sex and i had that reaction. I thought maybe he cheated and I caught something but he didn’t and I also got tested. I was negative for everything. I don’t dry up, I stay pretty wet the whole time so idk what it is. Has anyone else experienced this? Any tips?