In general, violence is of greater moral value than sex. This is for two reasons. First of all, you can kill multiple people during a war or in self-defense and retain a clear conscience, but the number of people you can licitly have sex with is a dichotomous variable with a value of either 0 or 1, depending on whether or not you're married. In addition, there is no sin in being killed, so at worst, a person who kills another is only harming his own soul and not his victim's. In contrast, having sex outside of marriage is a grave sin committed not by one person but by two. By leading each other into sin, those who engage in illicit sexual activity are not just committing the sin of fornication but scandal as well. Murder is a greater sin than unchastity, but the effects of unchastity can be even worse than murder.
That is not to say that at the individual level, violence is always superior to sex. Between spouses, sex is a renewal of the marriage covenant and releases sanctifying grace. That is of course worth more than all the just wars in the world. However, it is certain that a man is better off doing combat patrols in Afghanistan than cohabiting with his girlfriend back home.
This concludes our disturbing moral theology lesson for today.