Oooh but condoms are SUCH a nuisance!
That woman needs to be sterilized. I would suggest an IUD, but from what I've been told, if you're sleeping with every Tom Dick and Harry, you'll get an infection. IUD's are for women who are in a commited relationship. They also cause infertility, so it's perfect for a woman who's done having kids, but doesn't want invasive surgery.
Condoms break. You can get pregnant while on the pill. Heck your tubes can come untied, and so can a vasectomy. Face it, God made sex fun so we'd populate the earth :/