If you don't mind betting on this - it is more likely to be guy #2 as you had unprotected sex with him and it sounds like you had sex with this man more often.
Protected sex is not 100% so it could still be guy #1 but the chances are much less.
Only way to know for sure is to get a paternity test.
I am guessing that you don't want to tell guy #1 and/or don't want to tell guy #2 he is likely the father, than to just say with confidence he is the father. Unfortunately if you want to be truthful - you will need to come clean with guy #2. Let him know the situation there is a possibility he is not the father - how do you think he will take it?