Well, two things:
1) this game needs the cheating tag as the MC can be a cheating asshole and...
2) As for Louise and whether she is or isn't loyal. Obviously Cenc has said there is no NTR planned at all so I have to respect that. However, the shot where Sebastian picks Louise up and she is posing in the door was what made me think that she perhaps entertained the idea of giving into Sebastian's desires. As if she wasn't above using her beauty to tease and string Sebastian along until she got what she wanted (success). It seems Louise has decided that succeeding is more important than her husband's well being or their marriage - leaving him alone for hours on end while she goes and meets Sebastian and groups of people again and again in an attempt to become a successful artist (which is bizarre to me since it really shouldn't take weeks/months of meetings to decide if an artist will be displaying art in a gallery) instead of spending time with him while he is healing. The fractures he suffered take 4-8 weeks to heal completely, depending on severity. Also was weird that they waited until he was fully healed to have the funeral.
I stuck to the Louise only path, because I don't play cheating assholes, but I think I'm not going further with the game at this point. Don't get me wrong, I think the developer overall has a well-written and decently rendered game, but I don't really want to play a game where the MC is investigating the murder of his daughter and the serial killer who is courting his wife. Just not what I want to play right now, too dark a story line for me. Not that everything has to be rainbows and fluffy kittens but it doesn't seem like this is going to lighten up at all (and most likely will get darker). In addition the emotional investment in Louise isn't there to convince me to keep going, we met her, then 16 years passed, the daughter died (Sebastian rammed his car into their car?) and now the MC barely spends anytime with her. <shrug>
Anyway, hope the MC doesn't end up going too insane while sitting at home waiting for his wife to come back from an "artist" meeting.