Oh wow, I'm sorry for your losses. I'm not an expert, but I do think it's unusual for m/c to be caused by something in the father's genetics. Maybe a combination of the two parents, but I'm not sure. Have they done any testing/bloodwork as a result of your three losses? I recently had my third m/c, and my doctor offered genetic testing at that point. (I don't have the results yet.) I do also have 4 healthy kids, too, so I think it is probably just one of those infortunate things with no particular cause. Good luck to you. Praying that things will go perfectly this time.
I would question everything in his diet and medications because if this has happened to him before, it is possible it's something to do with his sperm. The father is 50% of what is going on with any fetus. I would definitely have him go in for a sperm analysis. Especially since you have had two normal pregnancies before this. Not to say that miscarriages are uncommon, but three in a row would give me pause in light of his history. It's worth a shot anyway. Even if this one progresses normally its still good to find out if anything is going on with him. Good luck!