The backstory of "likes group sex" doesn't even jive with the current version because Stef seems more interested in "any cock but the MC unless she has to" in some of the paths, not just different approaches to 3 and 4-some content with her AND her husband both included. In her backstory she said she eventually did start having sex with the two dudes and NOT have her bf included, so I guess we're supposed to infer that has carried over and she wants group stuff without her husband? That's how part of it's definitely been written so far.
And agreed, the game definitely started more like hotwife/cuck focus more than anything else.
Yeah though the chief difference in the backstory IIRC was that Chuck had set up those encounters that way, not her. It wasn't that she preferred having group sex with only other guys, it's that her boyfriend was whoring her out. Meaning I agree with you, this is far from consistent.
Chuck chose not to paricipate. This is a big stretch from her voluntarily excluding husband; if her past story 'reveal' was truly canon, you'd think the first thing she'd do at Jason/Tori's after starting anything sexual with Jason would be to yell "Get your butt over here mc, I want you to join!"
In fact, the more one thinks about how the game actually goes, the more they might realize how gaslit we've all been by the dev's story, like "Wait, this is a game about exploring swinging/sharing, threesomes, yet somehow at the current moment, events came together such that the wife is having sex with another guy downstairs, and I'm up here doing nothing?? This doesn't make any sense."