Does he think she is a slut?

It means that for one he is a misogynistic piece of **** - NO ONE should call a girl a slut, it's a term used not only to demean women but it's about control: using judgement to assign worth and control womens behaviour through shaming. It shows the guy in question has little to no respect for women at all, so shouldn't have a girlfriend at all.

If the woman doesn't consent to the video being posted then it's known as revenge porn, it is grossly immoral and depending on where they're located he could face serious criminal charges. If posting the video online was not consensual then clearly he didn't love her or respect her - she was completely within her right to break-up with him, but he's too immature to understand he was responsible for the break-up and he's wrong to treat a woman this way.

Who cares what he thinks?

His opinion on women is worthless, he is a sexist jerk who's not worth worrying about.

"Your girlfriend is not a slut. No one is a slut. Sluts aren’t real. Sluts are a construction invented to make women feel bad for daring to **** the way men do—which is exactly however they like. The term 'slut' assumes that a woman belongs to any man they sleep with—that vaginas are erasers that take on some of every penis we interact with and somehow, in the process, become dirtier. Used. Not as good as a clean, untouched vagina. Less worthy of respect, admiration, and love. Are penises used when they interact with vaginas? Based on sheer volume, way more lady juice gets on a penis than sperm gets in a vagina. But no, penises aren’t considered to be less worthy if they’ve seen lots of vagina. Because penises are supposed to seek out vaginas and vaginas are supposed to stay locked up in a tower waiting for true love. Isn’t that how it works?" - Dana Norris

Do you really think he could date Kim Kardashian, even if he desperately wanted to?

This guy is a jerk, plain and simple. Stop beating yourself up.