Well, is there a reason other than his age as to why you would think he's infertile? 50, especially for a man, is no where near infertility age. In fact, men can have kids pretty much forever.

I would absolutely, positively not rely on the rhythm method if you do not want to get pregnant. It is really not all that accurate and you can get pregnant even if your calculations are a day or 2 off, which can easily happen because of stress or whatever.

You also really just need to talk about it. If you guys are having sex, then it implies you are aware that a pregnancy can result (especially since you are both adults). If you are willing to take the risks, you really need to be willing to talk about them.

I got pregnant when I was using birth control from a guy that I just had a sort of "fling" relationship with. 10 years later I am stuck dealing with his deadbeat *** and I sincerely regret my flippancy on the subject of pregnancy. If you 2 haven't specifically made lifetime plans, I wouldn't just let myself become pregnant. Regardless of whether he has money or not, if you end up hating him in a few months, you are not going to be very happy to have to be dealing with him forever because you two had a child together.

I really am not trying to be hard on you, but I want you to think about what you are talking about. Sex without birth control in a fairly new relationship with no true level of commitment is not the best situation.

Good luck.