Not clear to me when/where Alicia met Peter and whether she and Will ...

I think Will mentioned that their "timing" kept being wrong, which I took to mean that they kept being at different places in their lives, whenever they got together.

MY take on it was that Alicia was like so many people I've known, who make bad choices because deep down they don't really believe they even deserve to be happy. So they pick guys who they KNOW are going to hurt them, but they do it anyway. Peter was apparently from a "good family" (i.e. MONEY and prestige), while Will must have gone through some tough times if he'd been desperate enough to make the mistake of taking some of a client's trust fund -- but he put it right back when he had second thoughts about it and knew it was wrong.

Will did the same kinds of things all lawyers do when they're fighting for their clients, but he was never the lying cheating sleazeball that Peter was. I found it interesting that, even in the final episode, Alicia was still thinking that Will was the one who got away, while she was finally going to divorce Peter. A bit late for that!

It's funny to characterize Will as a womanizer. When Alicia rejected him for the dirtbag, he was free, as a bachelor, to see whoever he wanted. The tattooed lawyer who made a play for him that didn't work mentioned that he'd gone on a "sexual sabbatical" after Alicia. In much of the series, he was waiting for Alicia to make up her mind and make the right choice for a change. If he saw other women in the meantime, that was only natural. He wasn't a monk.

And about womanizing, Alicia's lawfully wedded husband is the one who could never keep it in his pants, even with his loving wife waiting faithfully for him at home while he was out banging hookers. He paid Amber for kinky sex with his family's money 18 different times, by his own sworn testimony in court. And when he extorted sexual services from Kalinda in return for a favour, he was still married to Alicia.

Typically, though, Alicia held that against Kalinda, to whom it meant nothing, and was only a means to an end -- while she stupidly stood by Peter, who didn't deserve it. This cost her friends, self-respect, and possibly her job, too. That was the tragic irony of being "the Good Wife", that she'd stand by the wrong guy no matter what -- and it cost her everything.

In the first season, Alicia tells Will that, if she had chosen him over Peter, it wouldn't have lasted for more than a day. This suggests that, at one time in the past, Alicia was acquainted with both men, and in a position to choose between them. The three of them probably met at Georgetown as students, both guys liked Alicia, but she fell for Peter. Besides, when Will visits Peter, it is clear that the two of them knew each other well, and not through Alicia. As for who's a womanizer and who's a scumbag, what difference does it make? Just try to picture Chris Noth really young, the way he looked in L & O, and you'll understand her decision, even if you cannot approve it. Ideally, character should trump looks, but this is not always the case. Money and social connections are a different matter, unfortunately; they always trump everything else, but Peter was the richer and the best connected one. So it was just looks vs. (lack of) character, and when a guy looks like a young Chris Noth (or a young Bill Clinton, for that matter, since the show is full of references to this former and, probably, future first family), even very smart women like fictional Alicia or real life Hillary may skip the personality check and just go for it. This doesn't mean that they won't regret it later, it just means that we all make stupid decision under certain circumstances.