Don't look good for women, look good for yourself. If you just force yourself to work out through these feelings your having, it'll help you in the long run. It will produce endorphins, which will help you release stress and depression. Forcing yourself to go can also help you renew your interest in it, because if you put in the proper effort you'll actually be gaining energy by going, which it sounds like you need, not losing it.
I'd lost all my interest in the gym for a while too; it was like a chore, but after a couple months of pushing through it, I look forward to going again. So it'll come back, don't worry about it.
Plus, going to the gym regularly will keep you feeling great about yourself. If you let it slide and completely stop, one day you'll wake up and realize how drastic the physical change has been and be unhappy with yourself, which a stress you don't need on top of the others. Then things will get REALLY tough, because then you'll really never get your motivation back, realizing that you need to start from scratch and how much more work that is than maintaining whatever you have now.
Now, on to ez_e's comment about women being ignorant, brain dead whores:
First, I'd like to say that I'd choose the hot guy with the STD but only depending on the STD. Many STD's are bacterial (i.e. Syphilis, Chlamydia, etc.), which means they can be completely cured w/ meds to the point the person who had the STD would no longer even be a carrier. If it was a viral STD (HPV, HIV, etc.), I'm almost positive no girl in their right mind would get with any guy, no matter how good looking, if they had the chance at contracting a more serious STD.
Second, yes, most women want a man with a nice, strong body, but that has to do more with nature than being "ignorant, brain dead whores," as ex_e so nicely put it. All female animals in nature look for a mate that will give her the healthiest offspring as well as a mate that can help protect them, a mate who's altruistic. It's no different for us. It's not shallow, it's a natural want and need to find a mate that I can have good children with, though a women probably wouldn't know this is their natural, subconscious thought.
So yeah, if I see a guy in great shape who's healthy, I'm going to want to be with him over a guy who clearly doesn't take care of himself. If a man doesn't take care of himself, he's not going to take care of me or our future children either. It's survival of the fittest, and women want the best chance possible for their offspring to live long, happy lives.
THAT's the science behind women's attraction to in shape men, not a women's magazine study. It's not some shallow obsession with staring at a guys abs, while he's on top of her.