Obviously they were happy enough to have unprotected sex... and dumb enough not to realize after the first kid that that was a bad idea.
I don't even think people think Britney is evil for stealing him away from Shar. I think most people think it's tacky and kinda wrong for him getting engaged to her while there was a bun in Shar's oven that he helped bake.
I'm not sure if you understand the difference between child support and alimony. Alimony would be money going to Shar after a divorce, and they were never married. Child support is to help take care of his kids. Since Shar has custody of them, the checks do go to her to use for their care.
I also don't understand why you said so Shar can keep poppin' out kids. It's just as much Mr. Federline's fault... it takes two to have sex and get pregnant. That's a really bad double standard that sets women's rights back a few decades....
