Uncomfortable Sex

The idea of sex sounds great. I’ll be ready for it but when it comes time... it’s just really uncomfortable. I just hit my third trimester, so my back aches. My baby pokes and stretches my tummy in awkward ways. I get really wet (tmi sorry) but it’s like my insides are too tight. I feel everything in my stomach 😭. Anybody else have these problems? Any way to make things a little more comfortable? I feel bad because I’ll get my partner going - thinking I’m with it - but once we start, I lose interest and sometimes it hurts. He understands and has no problem stopping, I just feel bad & frustrated!