Most Helpful Guy
I can see him giving you the impression he cheated to give you a taste of your own medicine. He was obviously hurt by the fact that you'd give another guy your phone number and probably wanted to turn the table on you so you'd know what it feels like to think your partner isn't happy being with you. Being drunk isn't an excuse in my book. Alcohol lowers your inhibition but you meant all along to give that guy your number. If you were totally happy and secure in your relationship, you wouldn't have done it. Sober, you might have thought twice about it, but you would have likely wrestled with the decision, but a small part of you would have wanted to give it to him. Drunk however, you gave it away.
In the end though, go with your gut. If you don't want to take him back, then your body is telling you something. That there isn't enough love to forgive whether he really cheated or just made some bad attempt at making you regret what you did.
If you take him back, take him back because you love him and you see something long lasting. Take him back because you're both able to get passed this. Don't just take him back because people or friends tell you to. Listen to your head, heart and gut. If it's telling you it's time to walk away, then do it. Things won't get better from here if you're holding on to those nasty feelings and you have all this drama hanging over your heads now.
Most Helpful Girl
Im probably not going to tell you what you want to hear, but to me it just looks like he was trying to give you a taste of your own medicine. A drunk persons words are a sober persons thoughts. Obviously he was hurt about you giving your number to another guy so he tried to see how you felt when he gave you that type of situation where it is possible to cheat. What if his friend was a slumbag and didn't care if you were his friends girlfriend? You guys would have most likely fucked..
Whether you want to see it or not you were the one to start this mess so he decided to end it by showing you how it hurts. You shouldn't have broke up with him because you have no proof that he was cheating. Obviously there will be projects that he will most likely need help on or maybe he was just at home by himself because he was too hurt to directly confront you about it so he made up a situation.
If you do take him back, do it because you care for the guy and you know him better than we do on the internet but im pretty sure that's what he was doing. So, honestly that is up to you.
When I was with my ex I took him back 3 times.. -.- but just don't try to over do it or keep hurting him. Learn to control yourself hon. It will help the relationship. or the next party or bar take friends that you trust or even take him with you.