Yea well like I had already predicted, Lacey is corrupt, her end goal is to corrupt the MC so she can basically return to being a slut while keeping her husband because she love him and because she feel indebted to him, so she put up with being a good little wife just long enough to decide it wasn't good enough and start trying to bring him down a path which enable her to return to the personality she held during her College days effectively speaking. To get the MC corrupt she is basically breaking him down until he is going to be numbed to everything she does and let her get away with all of it, its a method of indoctrination, now she isn't really evil, just a slut that want her husband to support her into her slutty ways. Any notions her intent was to change for the benefit of the MC is ridiculous, she tried to change so she could be palpable to him, but in truth she clearly figured out it would be more satisfying to change him instead which I believe she was been doing since before Act I.
As for what was her motivation for College, let's be real, as I and others also said before it didn't really make sense, you don't slut it up as hard as she did just to try to overcome your issues with sex. Like I had said, I believed she had done it because she wanted to forget her past, to drown herself into some form of stimulus to dull her memories. Again whatever Lacey or the Dev say is always of questionable reliability, so its not too shocking it wasn't done really in the optic of what was originally said. Now for the matter of love, it can be complicated, some people separate love from affection, personally for example I don't attribute the term 'love' to anything else than romantic love. I thing the Dev might operate a bit on a similar premise, yes Lacey felt something for the MC but it wasn't romantic love, unlike him which did feel romantic love for her, so she left so she could figure out how to be capable of romantic love so she could give him want he needed to repay him for all that he had done for her. But it doesn't mean she didn't feel deep affection for him or anything, it just mean she was too hurt by what had happened to her before to possibly be able to experience romantic love specifically.
As for the ending, its clearly another one of those shock drama cliffhangers, something to keep people hooked until the next update come up and likely resolved minutes into the next Act, its a very typical tool employed by writers like this. It doesn't mean its a good one, its sucks, just like the last minute plot twist of his previous game, which is also a shitty thing to do. I know some people seemed to have acclaimed this Dev but frankly they aren't good writers, just employ tropes and artificially developed narratives driven by the force of will of the Dev rather than by a good narrative flow. Let me guess I haven't played this Act yet, waiting for it to be available for free, but I can guess the therapist is either in on Lacey's plan and is trying to help corrupt the MC or she is in on the plot against them and she is trying to break them up.