Your point of view is that people can't look at others if they're married or have children. It's as if somehow they stop being sexually desirable beings.
Oh no they can still be desirable obviously! Some people are just so pretty. But it's not good to like, think about them consciously. Unless you're dating them, like maybe you're dating a single parent. That's okay.
There's a huge difference between thinking someone is sexy and going and having sex with them. There's nothing morally objectionable about the former.
Well, maybe if that thought pops into your mind that's okay. But you can't encourage thoughts like that.
I mean, you CAN, but you shouldn't. And YOU can, but I wouldn't.