Abusive relationship?

What do you think an "abusive" relationship is? I mean, it's obvious if someone hits their partner but what something more subtle...like a partner who yells a lot, is kinda mean (even if they don't hit)? Also, is it abuse if someone cheats on you all the time?

[ewhite]

A relationship can be abusive even without violence. Aside from physical abuse, a relationship can be verbally, sexually, or emotionally abusive. A partner who is mean, disrespectful, yells or puts you down verbally can be just as unhealthy as a partner who is physically aggressive. I definitely think it's abusive if a partner regularly cheats. That violates your trust and is emotionally damaging.