While friend-code insinuates that whoever you were friends with first is the friend you stick with in the end, that's not necessarily how real life works. And it's not fair for either of your friends to expect that you'll dump the other. "It's usually an unspoken understanding that one partner exits with their friends and the other partner exits with theirs. The issue with that is that people often become super close with their ex's friends, so the lines get blurred," says dating coach Diana Mandell . And people shouldn't put their friends in a position where they have to choose who they'll be friends with. So step number one, if you're planning to stay friends with both people, is to set up some boundaries and be open from the start. You can't sneak around and try to hide that you're still hanging out with either of them and expect that the other won't find out.