You need to up your game. Though it's common for mothers libido to tamper down after a 2nd child, there are things that you can do to create more attraction.
If her desire for sex is down, the problem can be compounded by a husband that let's himself go. Many times we husband can get comfortable and not make an effort the way we did when we were trying to woo our wife. I'm not advocating non-stop effort but there has to be a balance.
A date night at least once a month can help. An occasional small gift just because. Also you have got to take care of your appearance. Make sure you're working out and eating right so you can keep looking good. Also don't neglect your hair, clothes, and hygiene. If your wife notices you're looking good, she knows other women will notice as well. That can spur her to up her game by wanting to bang you.
I needed to read this, and welcome more comments like it. While I don't believe I take my wife for granted, it's true that I don't put as much effort into "wooing" her as I used to. Sometimes things like buying gifts seems so impractical when you share a bank account. Like, "if you want something, buy it!" I know that's the opposite of what I should be doing, and I'm going to work on that.
Ever since the kids were born, I've put on weight. I'm not morbidly obese or anything, but yeah... you look at pictures of me 10 years ago, and there's a considerable difference. That's a whole other struggle in my life, but you're absolutely right. I need to take care of myself better. As far as turnoffs go, I realize that it's probably not just the fat... it's the fact that I allowed myself to get that way that is the real turnoff, and also that I can't seem to do anything about it. I'm going to work on it, I really am. But I feel like my clothes, hair and hygiene are good. I honestly think my wife is very good looking, and would maybe be out of my league if we were both single now and I tried to approach her. My wife says my weight issue has nothing to do with her lack of sex drive, but I'm sure it doesn't help. And like you said, if she would see other women looking my way, that'd probably zap her libido back to life quicker than anything. That's one thing about when we were dating / first married. I had a lot of attractive female friends, some of whom I had a sexual history with. We were all just in the same social circle, and my wife encountered these women quite a bit. I never cheated. She would sometimes get jealous, but I really do think that fueled her sexually. Now, 11 years into the relationship, and I have no female friends, no female co-workers... she's basically the only woman my own age I ever interact with (I'm 35). I would still be sexually attracted to a woman who has the female equivalency of my body type, but I realize that for women it's not that simple.