...you should be married.
and i'm not saying that just because i'm a Christian...
What's to stop him from lying to you about having STDs?
And if you get pregnant, what's to stop him from leaving you with a kid?
I know my opinion and reasoning prolly won't change your mind, but in the very VERY least...always use protection. ALWAYS.
And if he feeds you any crap about condoms making it not "feel as good", that is BS. If condoms really did take the pleasure out of it as much as they say, there would be alot more fatherless babies out there.
Just whatever you do...be responsible. And make sure he's trustworthy and that he cares about you enough to do what's best for you too.