How big is the chance?

Hi ladies,

I'd like to briefly introduce myself. I'm Farah, 25, and my boyfriend is 38. So far, we haven't had a desire for kids because we both have busy jobs that involve a lot of travel. It's not that we never want little ones, though. I'm actually wondering how long a man can really "keep it up." I know my boyfriend is much older than me (age is just a number for us), which is why I'm curious about people's experiences with older men.

Honestly, I think this month might be the one. I don't use contraception because I react poorly to hormones... but that hasn't stopped us from having unprotected sex. I'm on day 15/16 of my cycle, I think, and given how much sex we've had around the fertile days, I'm stressing a bit. A baby would be more than welcome, but the timing is just unfortunate... hence my question: how fertile do you think my boyfriend is at that age?

P.S. I hope I'm not offending anyone with my post.

Love, Farah