Just FYI for everyone, this handy <a href="http://www.fda.gov/fdac/features/1997/conceptbl.html">chart</a> give the percentage chance of failure for different birth control methods over the course of a year.
So if you're using a condom and the pill, even if you use the typical use numbers (which assume she forgets sometime and the condom breaks once or twice) the chance of both failing is 0.7%. So if you two have sex for 100 years, she'll get pregnant, on average, about once. Basicaly, you need to realize that the fear of pregnancy is fairly irrational.
Now that doesn't mean that its not a totally natural irrational fear to have. I showed this chart to my girlfriend (who also would not have an abortion) and damned it she doesn't still freak out everytime her period is 12 hours late. And damned if it doesn't put me on edge a bit too. So really, for me at least, its not a question of whether we can support a child (or survive the stress of pregnancy and childbirth and give it up for adoption) as much as is the stress and fear we go through worth the sex? It seems to be putting you through a lot of stress, so I would suggest not (remember BJs are fun!
) especially when you factor in the 0.7% chance per year that she would actually get pregnant.
And for the record, every time my girlfriend freaks out, I say we should stop having sex, and I very nearly mean it. She actually called my bluff once and we went a month without before we both caved. So I don't feel too hypocritical counseling abstinance.