Sex has been one of the major driving forces behind every decision I've made since I turned 13 or so. How I dress, how I talk, why I buy the things I buy and 50% of why I wake up at 5 am to go to the gym, why I go out to obnoxious bars and clubs... how is that not a 'need'? In the hunter-gatherer sense I guess it's not since I won't die if I don't have it but the want to have it as much as possible controls a huge percent of my daily actions. So maybe an 'addiction' then? Fine but now we're splitting hairs.

I would ague that marriage is not a need. It's an artificial construct that we impose on ourselves in a time when we don't need to do it. Women don't need you to survive, they can be their own providers now.

And why do you need to be betrothed to one woman for all eternity? Nature would love for you to spread your seed amongst many more women - larger bio-diversity.

But nobody is stopping you if traditional marriage is what you want to do, of course, more power to you.

While this is technically true, it's stated a little too glibly considering that we're talking about life-or-death (over the long term) evolutionary drives here.