B.B.
They are very effective. After 10 years (I think) The effectiveness goes down 3-4%. You are probably OK. I'm not judging, or anything (you're an adult after all), but I would seriously consider using protection. There are so many terrible STDS out there, it's just a bad idea not to. You not only sleep with that person, but with every person they have, every person who has slept with them...so on, and so on. You don't know the persons health and sexual history. A one night stand puts you squarely in the "high-risk lifestyle" category. You would not believe how common STDs are. Why take the chance? ESPECIALLY, if you already have children. Would you want to be taken from them, for something so preventable. For meaningless sex? Not worth it, in any scenario.