Just to be super picky, we're not talking about the main character here being lesbian, we're talking about her being Bi. She obviously likes men.
She's married to one, but it doesn't mean she always has to like men. You can see cracks in their relationships with the way Liam works so much that he's hardly ever home and he has a serious gambling problem. On the GW route, these issues are overlooked, but on the other paths these issues are more stark.
Sophia is also a very sexual being and on the non-GW paths she's growing ever more frustrated with her husband's absence and with his general lack of attentiveness. In steps several characters - Dylan, Sam, Patricia, Ellie, Alyssa, Nathalie - that show her both affection and attention, and thus she begins to feel temptations she didn't know she had due to her frustrated and pent-up state. She can and does often find that these characters show her more care and affection than he husband has lately and it's easy to see how she could fall out of love with him and in love with someone else, and that could easily be another woman.
LoL will do. Game looks great, but don’t want to play if there is little pay off.
There is some pay off with certain things, but in terms of her having sex with anyone other than her husband, we still have quite a ways to go before we get there.