What can help Boost male fertility?

So me and my fiance have just hit the one year make on ttcing and no luck. I have been trying to get healthier for the sake of trying to better out chances. But him not so much but I think I could get him to at least do something so.. is there any kind of vitamin that he could take to help his fertility? I plan to go to a fertility clinic soon but in the mean time I figured we could try something else