What do you do when you've lost your libido?

My husband says I never want to "do it". He's always the one who does. It used to be the other way around when we were first married. Back then there was a lot of hurt (I was hurt), he seemed to grow very cold to me (during my 3rd pregnancy). He became verbally abusive...impatient with me, and almost never touched me for long periods of time. After a while of trying to gain affection, and make him understand that he can't treat me that way...trying to win his approval, and getting nowhere..one day something seemed to just fade, break away. I felt like I didn't care anymore. I am no longer ever in the mood to do it with him..I am pretty sure that it's not my libido that's having problems, cuz I will feel "in the mood" at times (at least 1x a week), but don't say anything to him cuz I don't want to do it with him, I feel uncomfortable when naked, or during sex, cuz I am overweight....I've had 3 kids in a 4 year span...have not lost weight, and maybe gained some due to depression bcuz of marriage trouble. I am not so hideous, but I need to lose the weight. He makes remarks about it now and then, so I don't feel comfortable naked around him/ or anyone for that matter...who does? Anyways, The fact that he still wants to be intimate with me, isn't something that I feel so great about, cuz when we do it, it's boring, that's all we do, no foreplay, no, just his relief. He says that he's too tired to bother with "messing around". Now that I never want to do it, he asks, but I am just not into it. I feel like he's a friend, a lifelong companion...not a lover. He has a hard time showing affection and had an emotionally neglected childhood, but he has shown me that he can be affectionate (and was all during dating and first year of marriage), and even a little freaky in bed when he wants...so my being fat is a turn off to him, I believe. I want to lose weight, and get back to my old size, but it nver gets anywhere..I just feel so low and ugly. I've noticed he's been paying more attention to attractive women...online..not porn, but like an ad or article with ladies in bikinis..Normally he doesn't go clicking on those things...I know cuz I check stuff on the computer.