When you are intimate with someone else it is cheating, emotional or physical, it is cheating. A lot of people do the emotional without thinking they are. It can hurt relationships even though there is nothing physical. If you want someone else, the current relationship needs to stop, or you need to talk to that person and tell them what is going on and see if it is time to end it or maybe have an open relationship. If your interested in someone else, you shouldn't be in a relationship with anyone else but that person. If you can be 100 percent faithful, than the other person should know.