When did the cheating occur in this scenario?

Without knowing exactly what sort of understanding Alan and his wife have about what is appropriate in their relationship, we can’t say when he first cheated. As Sebastienne noted, different couples may draw those lines at vastly different places. That said, in my mind, the first moment where Alan definitely crossed some sort of moral line is when he first lied to his wife, since that’s when the deception began.

Obviously the real answer is, there is no strict cut off point. He started off with tiny cheating and gradually escalated into full blown cheating. I answered #2 though. The first time something happened, he was caught off guard and it could be written off as flirting or seasonal tradition. But the key part is when he started lying about it. The part of cheating that is bad is not any particular thing you do with another person, but instead whatever deception you get involved in to hide the behavior.

This. The lie is a sort of “explicatio non petita, accusatio manifesta” (something like “an explanation given without having been required is a self-accusation”): if you’re making excuses / lying, it’s to cover up for something. You don’t cover up innocence.

If they had a mutual understanding, he wouldn’t have had to lie to his wife.

I had said that he cheated when he got the blowjob, but really, I think it was when he got the handjob. Everything before that, while it was flirting, wasn’t cheating, because they hadn’t had sex.

When he kissed her. Though, frankly, he might as well have been cheating from the start because since being kissed it seems all he’s done is think about her.

Hmm - this makes me think that we should start another poll on cheating - what people consider cheating, with or without touching/sex.

To me, when Mia becomes the object of pursuit, he’s cheated.

The Christmas morning scene where Emma thnks Alan has purchased the gold necklace for her, and she opens the Joni Mitchell CD he actually gives her, and she removes herself from the family, goes quietly to pieces in the bedroom, then comes back to the kids with a smile on her face, is one of the bravest, most painful scenes in the movies.

StG

Absolutely right. If you aren’t doing anything wrong, you don’t feel that you have to cover it up. By lying, he demonstrates that he’s doing something he can’t be open about with his wife, which is a major red flag.