I was poly for about a decade. There’s a lot of solid advice in this thread. The only point I want to hammer home is the amount of drama inherent to human relationships increases significantly. It doesn’t just double: going from a two to three person relationship it quadruples.

Nothing disastrous or even bad happened due to being poly. I don’t regret it at all and would consider it again in the future. When I met my current partner and they said they wanted to be monogamous, though, I was happy to take a break.