Alex having sex with Lana would be nothing new. If I recall correctly he has sex with her in chapters one, two, four, and eight. And in chapter eight, we've already seen a jealous Daniel:
The question has never been whether Alex wanted to have sex with Lana. I've said this before, and I'll say it again: Lana's reasons for cheating on Alex are actually quite silly. But to be fair, a lot of her attempts to justify cheating on Alex happened when she was inebriated. I think it may turn out just as Dustellar mentioned in that Alex's increased virility and stamina as a result of that pill will make Lana realize that even though she's having more sex with her husband--what she claimed she wanted--she still prefers her son. And that realization may culminate into Lana eventually, both internally and externally, accepting Daniel as her lover. Chapter 11 ends with her questioning whether or not she wants to save her marriage, and the Chapter 9 cover has an image of her removing her ring, so maybe these are the series of events which lead to that.
