Sophia's already on her way even though their last event at the hot tub still required some wine to loosen Sophia up. Predict in this event, Sophia will no longer require drinks to bypass her inhibitions. Sam is her young Springsteen fantasy. She thinks highly, and now hotly, of Sam. And add in the little things, like their cello lessons and Sam offering to pick up Ellie, that further deepen her affections too.
Sam and Andy are the top candidates for Sophia to hook up with from where I sit. Also, possible that if Sophia turns down the swinging proposal, it could put a rift between her and Liam, who is all gung-ho about the idea, making Sam an even stronger candidate.
Plus it would make for good drama.
We seem to be playing different games!
The last event with Sam ended with drama, with conflict (even if the player could defuse it again by letting Sophia decide that Sam will pick up Elli from the beach).
This time Sophia will go into the meeting scaling back the relationship with Sam to the normal level. She has to, she wants to protect her marriage and her life so far. This means to me that Sam has to bring out the big guns to turn this situation in his favor. That means the use of alcohol and/or the sympathy ploy and a silver tongue from Sam that will make reading the dialogue almost unbearable.
However, Sam could also force a decision from Sophia. When he coaxed the statement out of Sophia that she could imagine loving Sam in another life, it was similar. In this situation, Sophia could say: "Yes, I want to, but we have to be careful. But that would be the point of no return. The point at which Sophia admits that Sam is more important to her than Liam and her family. This decision should then have a great influence on the further plot. Since Sophia then, if she continues to have sexual contact with other characters, and not only Liam but also Sam cheats.
Since L&P allows such a decision at this point, I would doubt and therefore rather bet my money on the first possibility - the one with the alcohol.