Is it possible to forgive a friend who slept with your boyfriend/husband or girlfriend/wife?

You can forgive but it's near impossible to forget. The friend will have a long road ahead of them to ever be really trusted again. Each situation will be different of course. The person who was cheated on will have to ask themselves why the situation happened. Is the friend someone who is prone to needing affection or attention? Was it a drunken night and do either parties involved have an alcohol problem? What's going on in your relationship that your significant other would cheat on you? There's a ton of questions to ask and the questions will vary based on the situation.