I mean the routes that blow up (Making out with Eryyn and dating alexis : Dating both Alexis and Layla) are because MC is fucking around with two people close to each other otherwise I don't think MC has had the exclusivity conversation with anyone until he says goodbye to Cara/Nikki at the airport if the trip goes well.
So whether you are dating Alexis or Layla I think if you are honest about Nikki/Cara (and honest with them about dating someone) coming to visit it's not quite cheating (same with Valeria).
So sure the paths will eventually all be solo paths but currently the MC can still be on many different girls paths. (I think Eryyn and Alexis are more likely to end a throuple then Elena/Layla especially after MC saves Eryyn and she finally confronts her feelings for him)
It blows up only if the MC turns Layla down and goes meet with Alexis. If not, the story lets it slide (but I can't). So it works as intended only once. Just FYI. Ep. 10 is good at forgetting things. Hopefully, Ep. 11 shows us Erynn telling Alexis about that day the MC and her made out and were about to have sex.
I think when you go back to Alexis it's implied that "now it's gonna be official", so any messing around past that point might/will be construed as cheating.
Thus far the game allows you to "dodge" the Erynn bullet, let's see if there will be future consequences on that one...
She certainly doesn't take super well to you messing around with Erynn(if you don't dodge it), she definitely thought it was cheating.
Erynn is unsecure on what she wants because of her past expiriance. And i think others explained pretty well. Because of Ethat, whole video situation and blackmail she doesn't know how to give in, like be with MC if player is on her route. On the other hand she's jealous of pretty much any girl that may be involved as gf of MC. Take Layla for example. After the nightclub party with Layla, Elena and Zach if you chose to go with Erynn she asks about Layla, whether MC likes her or not. And i don't think that because MC is her friend and she's curious. I do however think that she's also slowly opening, especialy after Episode 10. If you're on her route there's cudling scene with between MC and Erynn.
This is different, she's always insecure, yes... but when you are doing Erynn with Alexis, you can see there are scenes to show that she's hurting inside.
For example the
bed scene starts exactly the same, except instead of cuddling she just backs off turns cold and stares at the ceiling.
When you play both versions the differences become very noticeable.
I do agree that in "pure Erynn" there are signs she's getting closer to opening up, the cuddling was a lot more romantic and personal vs the conflicting emotions from the scene after the Ethan slap.
