It only takes 1... so 5 million seems pretty good odds - lol... Sorry, I don't have any words of wisdom - just trying to lighten the mood :o)
Aw, poor DH! That sounds like something that would happen to us! Honestly, I've never had an IUI, but if you take 75% of 5 million, you're left with 3.75 million, so that still seems pretty good to me. The IUI eliminates the 1st part of the journey for them, so that definitely increases their chances of getting there. All you need is one of those little guys to make it, and they have 2 big targets now, so I think you'll be just fine. I hope the 15th gets here quick and you end up with your BFP! Good luck to you.