My Husband Is Having Trouble!

R
My husband and I are TTC. He talks about having baby #2 more than I do! He's picked a name, bought me OPKs, HPT, and is the one to say, "Hey, let's go try to make a baby!" Haha. He's 24. These past few days during my fertility window, he's been having trouble getting an erection or keeping it once he has it. He is getting frustrated and stressing, even though I tell him it's completely fine and not to stress. I try to help him get rid of the stress when it starts happening and all, but he's letting his stress get to him and that just makes it even more difficult to maintain an erection. Anyone having any advice on what to do? I'm a nurse so I know all about medications, tests, ect. His testosterone levels are fine. But we want to go a more natural route regarding medications to help