Sex while pregnant?!

So I'm officially 5 months pregnant and still currently have sex my libido has not diminished, however since I hit about 14 weeks I've been unable to reach climax during intercourse. I want to so badly but no matter what Prego friendly position I'm in I feel uncomfortable and scrunched up. I enjoy solo time because I can actually reach orgasm. I almost want to tell my partner that this just isn't working anymore right now but I really enjoy being sexually intimate with him I've just gotten so big I feel like I'm suffocating the whole time and I'll almost feel guilty by saying no.. I just don't know what to do!