Well my husband definitely isn't pregnant, but after we got back from our honeymoon, he was constipated for almost two weeks! It was awful! We tried all sorts of stool softeners, laxatives, etc. Finally he had to take an enema (so glad he doesn't get on here and read this or I'll be in trouble for sharing!) and that got things going!
I agree, try a stool softener! Or like Jenn said, maybe certain foods? Pardon the TMI, but I know that sometimes really spicy foods will do it for me, or really greasy food. Not that greasy food is good for you, but hey if it helps!