I put DH on Blackmore's Men's Performance Multi as it had a zinc content in it that I researched at the time (appropriate amount) as well as something else geared towards boosting the swimmers. Sorry I've thrown the bottle out now (the vitamins did their job and DH is now overseas) but you could probably read about the product on the Blackmore's website.

HTH.
Good luck on your TTC journey - hope your efforts pay off really soon!