How much of a risk am I taking?

Ive been with my boyfriend for 6 months. We started using condoms and then eventually it dwindled because we both got so turned off with all the messing about involved we gave up. We now use no protection but my boyfriend pulls out before he finishes. I did this for a year with another boyfriend a few years back and no pregnancy. My current boyfriend is 25 and I'm 18, will pulling out lessen our chances of pregnancy AND the fact he's twenty five and could that affect the ability of his sperm? Ive tried the pill/ patch and it is a massive no no.