I’m a poly female. I messed up. I’ve been dating a wonderful guy for a year and 4 months and have been dating another guy for 2. Guy 1 knows about Guy 2 and thinks Guy 2 knows about him. Guy 2 doesn’t know I’m poly and frankly I’m terrified about what will happen if either finds out about the situation. I love them both.
You are cheating on Guy 2. This has nothing to do with being polyamorous, and please don’t tie up your mistake with polyamory, because that hurts a lot of innocent people.
You’re terrified about what will happen, because you know that it’ll be bad. (Now, if you’re genuinely afraid for your safety and fear either man will react violently or threaten your property, job, finances, digital security, etc. you should take steps to protect yourself. But if it’s just the dread of a painful relationship meltdown, that’s different.) Guy 1 will likely feel hurt, confused about your ability to misrepresent your relationships, and doubtful about your trustworthiness. His respect is important to you, and you don’t want him to know that you have done this. And Guy 2 will also feel betrayed and angry. But the longer you hide it, the worse it’ll get. You say you love these people, but love does not mislead, lie, and betray trust.
You need to come clean immediately. You need to tell both Guys what’s been going on. Some mistakes can’t be undone, they can just be faced. There is no way out of this that lets you off the hook for that really hard conversation. Explain what happened, take responsibility for your choices. You can let them know that you regret it and felt powerless once things got out of hand, but they are not obligated to see things from your perspective. You can let them know that you care deeply about both of them and would love to stay in a relationship and try to make it work, but again, they don’t have to accept.
It’s possible that you can salvage one or both of the relationships, with a lot of humility and listening, but it’s not something you’re entitled to and honestly not something I’d count on or even set as a goal to push toward. Your goal right now is to not further hurt the people you’ve already hurt, start being your best self, and treat everyone involved with the respect they deserve. And please, again, leave polyamory out of it. This is not the time to try and educate Guy 2 about the joys of non-monogamy or to explain to Guy 1 how your self-represented polyamorous identity has something to do with this.