Every relationship has it's unique way of existing and for most of us that isn't the concern. Everyone will have their opinion when it comes to the relationships of others, but the opinions tend to sound off in unison when domestic violence is in play. When communication doesn't get the job done, emotions and bad habits start to take over.
Couples get into the bad habit of becoming aggressive and physical with one another when they can't see eye to eye. If you have to physically fight your lover for peace in the relationship, I strongly urge you to re-assess your understanding of love and happiness. Love doesn't come in the form of physical fights and happiness isn't hidden in between the black and blue marks. The term Domestic Violence (DV) sounds serious so if you slap him in the face every now and then and he responds by throwing something, you might not consider that as serious and not realize the importance in labeling it as such. Putting your hands on someone else with the intent to harm them, especially when emotions are running high, should not be acceptable no matter how you frame it.
Being in a relationship through the thick and thin is one thing, but when you have to sacrifice your safety it's a problem. Love yourself more than you love your partner/spouse/lover. If you have children, you should re-read the previous sentence. The most significant way children learn what love is, is by watching their parents. You are their first and many times only relationship teacher in life, teach them what's right and remind them of what's unacceptable. Don't settle and don't sacrifice your safety or peace of mind, violence shouldn't be normalized in a relationship.