Most Helpful Girl
I think one thing that many people who take "breaks" fail to do is define the terms of the break.
What do they mean by "break"? Does it mean we're still together and just spending some time apart? Does it mean that we've broken up, but we're planning on getting back together after a certain amount of time? Is dating other people allowed? Is having sex with other people allowed? What is the purpose of the break? Etc.
If you do not have this discussion, then you're opening yourself up to this problem. One person may think a "break" means something different than the other person thinks it means.
If the two of you agreed to not have sex with other people, then it is cheating. If the two of you agreed to spend some time apart, but were not "broken up", then it is cheating.
If the two of you did not discuss any of these things, then its kind of a grey area since you're both on a different page. You feel like you've done nothing wrong; he feels cheated on and hurt. If you want the relationship to work, you'll both have to be understanding of how the other feels about the situation (rather than both trying to be "right").