Having been in love before and in a long-term committed relationship (with an INFJ no less), I get why they're so popular. It's really cool to have someone who you get along with so well that there are very litte pretenses or façades or judgment. It's cool when someone's emotional well-being is equal in importance to you as your own quest for understanding and knowledge.
However, it takes a considerable amount of energy for me to be in a "loving relationship." And I'm sure it takes a lot of energy on the other person's part to be in one with me. And I'm not going to put in the energy if I don't see/sense that the other person will match me in that.
So sometimes my feeling will tell me "aw, wouldn't it be nice to be in love again?" but then my rationale will say, "yeah, except for the long, arduous and often humiliating process of getting there. I've got WAY better and more interesting things to be using that time and energy pursuing."
At that will be that!
And I guess, for me, relationships only enhance my existing life, they're not an integral part of it. I have waaaay too much fun on my own. So I guess guys kind of have some stiff competition.