Do you see a future with him Britney? Has he got the same ideals as you and want roughly the same things out of life? Most relationships end with a break up for one reason or another or we'd all end up with our first love. Perhaps it really was time to finish it anyway. If the infidelity was the only reason you split up and you are sure it won't happen again, fair enough, you decide if you have another go at it. If the infidelity happened because basically he is a person who cares about a bit of fun more that hurting you, perhaps you might be better moving on. You've already done the hard bit. It's quite common for someone to have a relationship where they want to be monogamous, then miss their single life, do "something wrong" to get out of the relationship, live a single life, miss a warm one to one relationship, go back to a monogamous relationship. It's a "grass is greener on the other side" mindset and very hard on the innocent bystanders. If you have him back because it's a more comfortable option than being independent and open to trying another relationship, maybe you will have cheated yourself.