That entire show is a hallmark of the double standards we hold men and women to. Women can be downright bitches and it’s “empowering.” Men can be bastards and it’s “chauvinism.”
People wonder why I mainly watch cartoons on television. Sometimes they’re the most intelligent thing on.
Well, there’s a wealth of shows out there depicting male promiscuity with nary a consequence; they just don’t get fixated upon because they’re two a penny. I’d say it was primarily SatC’s relative novelty in reversing the roles that led to it being celebrated in the way you describe. There’s no shortage of people (of both genders) willing to point out what a lousy show it is as well, so I’m not sure there’s really a double standard at play.
With you on the cartoons, though. 
So Samantha is supposed to stay in a relationship she isn’t happy in forever because he nursed her through cancer 3 years prior? Her problems with him weren’t about her wanting to be with every available man, her problems were that she had given up who she was to be with him. She moved across the country even though she loved NYC to support his career. She gave up much of her job to manage him and his career so he could be a star. She cooked for him and made him sushi despite the fact that she is the kind of woman who probably used her oven for storage space. She was losing herself as a person and that is why she ended it. Wanting to bang the hot neighbor was just another clue to herself that she was unhappy. Not to mention she ignored her unhappiness for months because she loved him and wanted to stay with him. No one, male or female, should stay in a relationship that makes them miserable because they feel they owe it to the other person.
I don’t know, but I do know there’s nothing admirable or heroic about her dumping him, and I also know that a male character who did the same would not be perceived as sympathetic.
None of this rationalization would be seen as excusable for a man doing the same thing.
I don’t think anyone is saying that, per se. But the whole, “I love ME more, and I love you, so that’s why I’m dumping you, blah blah blah,” sounds shitty.
There’s a better way to end such a relationship.
Oh well, the show makes me sick, either way. And I’m only going on what I’ve read here.
This thread is starting to sound like the discussions about male versus female teachers diddling their underage students.