I wouldn't say he's really cheating on her. She's made it clear that if he sleeps with anyone else, she's gone, but they don't really have rules in their relationship; Sven knows where Faye stands on the issue, but he's only obligated to be exclusive with her if he wants to keep their thing going. He seems to want to, but he's allowed himself to get swept up in the moment and the drunkeness.
Still, sucks for Faye. I doubt this strip would come up unless Faye is going to find out somehow, and this'll probably ruin all chances of her admitting her feelings for him and actually having a relationship with him. It may seem cruel, but I'm interested in how this'll effect her. She'll be angry, obviously, and stop fooling around with Sven, but has she made enough progress with her abandonment issues for this to just be a break-up? Or will this seriously and deeply effect her; she was previously so scared to enter a relationship for fear of abandonment, and this is her first semi-relationship since her father's death, so I'm wondering if this is just the thing to destroy all the progress she's made.
Very interesting strip. Can't wait until Monday.