Don't engage in behaviors that are abusive to yourself or others. If you have problems with you temper, alcohol abuse or other issues that could lead to abusive relationships, get the help you need. If you ever hear yourself trying to justify another person's treatment of you, reconsider the relationship. Abuse is not a normal part of a relationship. There could be trouble in the future.
Disagreements are part of life.
Learn constructive techniques for disagreement. Remember that verbal disagreements do not ever justify physical abuse. Practice assertive communication skills. He won't get your subtle message, only the message that you'd love to sometime in the future. This is especially important if you suspect the guy might be of the violent sort.