Should couples fight in a healthy relationship?
That depends on your definition of “fight”. If your definition means some kind of disagreement, those are inevitable in any relationship, romantic or not. No matter what kind of relationship it is, neither party should physically strike the other person. It doesn’t bode well if this occurs. If you do have a disagreement, the best thing to do is to sit down and discuss it as a couple. If this is done in a friendly, non-confrontational environment, it tends to get resolved and apologies get said.