<human>: Can you summarize the given text in a few sentences?

I was dating this guy for two years, it felt pretty serious. He decided to leave the states for half a year without ever consulting me so I broke up with him. 

Our sex life was not so great. We lost our virginity to each other. He believed we would only have sex with each other. When he left I ended up sleeping with someone. I believe its really important to experience life and its wonders so I did it. 

He is coming back in about a month and well we've been talking here and there. We want to get back together. I don't want to tell him but I want him to know. I need advice.
<bot>: I broke up with my ex with reason. The sex was a problem so I experimented with someone else. Should I tell him I slept with someone else?