I lift for a lot of reasons.
If I DO NOT lift... my metabolism is so freakin high I wilt away to nothing. 3.5 months ago I was down to 180 pounds. I felt like if I got into any kind of physical altercation with it would end with me on the worse end of the deal. Thats not usually the way it is with me hehe. Im an agressive, very physical person (former D1 college football player). So I said screw this, I gotta get some size back on me. So I hit the gym hard.
I lift for me. For the self confidence it gives me. I am married and could care less about the cosmetic side of it (now... this wasnt always the case of course). But I do like that anytime I step out of the shower, or have my clothes off I can see my wife drooling over me out of the corner of my eye. It rocks. It makes me feel like the man.
I also lift because of the overall energy that I have while I am working out. I feel phenomenoly 10 x's better when I have been working out consistently than when I havent been.
Just overall, lifting makes me feel good about myself in so many ways... To say I do it for the opposite sex alone would be innacurate. Lifting helps me keep the depression of daily life at bay!