Pregnant PLEASE READ.need advise

So me and my long term bf broke up i started seeing someone else and that ended very fast then I started dating my boyfriend again..i found out im pregnant it could be the other man's child( me and my boyfriend were trying before without any luck) my boyfriend knows, he says he don't want a blood test, I feel that's unfair to everyone .but the man I was with was my childhood friend and he's being deployed in 6 months and won't be back for 3 months. I feel like a bad person if i dont say anything, also we all live in the same small town so he will see me around with a big belly that would be hard to hide then a baby..so do I say something or do what my boyfriend says and forget it???