i havent read all the posts in this forum but would like to add my thoughts also. It could be either mans baby, and who is to say your hubby's sperm doesnt have issues and therefore the other mans got to the egg or vice versa, concieving is a very involved process, TRUST ME!

also ive been in a similar situation, my DF cheated on me 3 months into our relationship WITH a pregnant woman, she was too far along to say it was his but what is worse he gave me an std from it which caused alot of our fertility problems. He didnt want to tell me but if he hadnt and i found out once the disease had progressed to making me possibly sterile he would have taken more from me than my heart. The thing is these things come out in the end, i forgave him and he has become a new man it took almost 3 years but we are happy together and it does still haunt me sometimes but im glad he told me, if he hadnt and it came out years or months later i would have kicked him to the curb beause i would have felt betrayed everyday after it happened and he didnt tell me, not just after the one act. Also perhaps get tested for possible stds, they will with routine preg bloodwork anyway. I hope things work out and thati havent offended you but i thought a perspective of the otherside might help in your decisions.