
I'm sorry you have to deal with infertility, it is so hard to go through.
My DH and I have a 2-year-old son who we conceived within 6 months...we had no idea we had any major fertitlity issue since we conceived without too much trouble. We found out while TTC #2 that my DH had a VERY low sperm count (his worst was 1.3 million/ml with 36% motility. Really bad, his urologist couldn't believe he had fathered a child). He has been taking tons of supplements ever since, and he also had a varicocele repair surgery in September. His SA in December had improved quite a bit to 12 million/ml with 50% motility and the total count was actually in the normal range.
I'm not sure how to encourage your DH to take his supplements. I do have to remind my DH to take his ( I also have pill reminder boxes) and he takes a TON (like 15 pills a day) of vitamins and supplements. When we found out about his severly low sperm count, DH said he would do anything to have anything to have another child and I remind him of that when he complains about taking his vitamins

. Has your DH seen a urologist to diagnose the cause of his infertility? There are things that can be done to help, and maybe it would convince your DH that there are lifestyle changes he can make to improve things.
Good luck!