I'll tell you what Celine's real issue is----Jesse's fatal flaw
A great job has been done here analyzing the ins and outs of their disconnect and who's 'right' and 'wrong' on what points, but here's what it all boils down to, deeper than Chicago or her career or either's infidelity....
She ain't getting laid proper.
Jesse's clearly sunk into a sexual complacency of the very worst kind. Her infamous attack on his prowess isn't just a cheap shot....his foreplay before the phone rings confirms it. Nothing exciting is going on here, erotically. Actually, I found it disturbing. Almost like he was paying some creepy homage to the Mother before plunging in to get his rocks off.
The ripples of this are endless. OF COURSE any woman erotically unfulfilled will lash out in the end. He takes it for granted (in a very American way) that enthusiasm equals ability. She complains in 'Sunset' that French men aren't near horny enough, and that may be true---but she also doesn't want to just get railed by an American teenager. There's an entire world of subtlety in sex that he seems to have missed.
This wasn't always the case, evidently. She's looking pretty satisfied that morning in 'Sunrise,' and I don't at all doubt their reunion in 'Sunset,' minutes after the film ends, was electric as all hell, for both parties. But somewhere down the road, he got complacent. She's known real passion and he just ain't providing it lately.
If anyone objects that there's more to a relationship than sex, of course there is. But sex is the bass line, the inner dynamic and rhythm of a union. It doesn't have to be constant or fiendish---unrealistic after many years---but it's got to have depth and be right on the money. And it isn't. This sounds pretty out there, but I truly believe that their outer problems stem from this. We can only hope he makes good on his word at the end, and redeems both the evening and their alliance together.