Sex during pregnancy

Ok so this is a bit personal but ever since my husband and I found out we are expecting (we found out around 4 weeks) sex has been so incredibly uncomfortable for me. Very very painful at times. I feel terrible because I can't give my husband what he needs. He's very understanding and suppoertive but I still feel bad because I want to be intimate with him but it is so painful I can't. Is this normal? Has anyone else experienced this? I always hear how pregnancy sex is supposed to be the best ever. Btw I am 18w6d now