I love your success story. Congrats on the pregnancy! My DH was on clomid and I wish it worked the way your DH's did. His actually did the opposite. His count went from 16 million to 2 or 3 million after being on clomid for 6 weeks. Our RE took him off and said his counts would go back up as fast as they went down. I wish it would have worked the same way for us. It's weird how people bodies respond differently.
My DH also has a low sperm count. When we would go for our IUI's they would be under 5 million. RE sent him to a urologist who ran some tests but could not find anything. The urologist put him on clomid 50mg everyday and told us not to expect any changes for a few months because it does not work for everyone. But the next month for our IUI his count was up to 36 mil the fist time and the next day 76 million. I also started follistim injections that cycle since I have problems too.We are now 20 weeks pg after trying for 4 years. If your DH has not seen a urologist, I would not put off going--we waited and waited before he went and I wish we would have just done it sooner. I think that really worked for us-although I did get pg once before (prior to him taking clomid) but it ended in an ectopic. Good luck to you and as bree08 said it only takes one.
My DH also has a low sperm count. I've read alot of places that to do IUI most DR's would like at least 5 million sperm. Miracles do happen though and it only takes 1 sperm to get you pregnant. Did they tell you why his count was low? Good luck. I hope you get answers soon :)