It's very simple for him to get a sperm analysis done. Just have him call his doctor and they will give him a referral. My SO just got one done a couple of months ago and they gave him the results right away and I was able to take them to my OB/GYN doctor. It takes a lot of work out of the guessing game and if it something to do with his sperm, then there are supplements he can start taking now to help or correct the problem. Good luck! 2+ years is long enough, have him go now. You should also request to get a HSG done to make sure your tubes are open, those two procedures are the most important ones.