Did another playthrough the other day to check out a few different scenarios in chapter 9, and I gotta say: The amount of variations Eva needs to account for in the new Lena/Ian relationship is absolutely mind-blowing.
Suddenly there's three different relationship statuses to account for instead of one: uncommited, open relationship, and commited relationship. And then there's the question whether Ian and Lena are OK with the other's current sexual relationships or not—and whether their sexual partners are OK with Ian/Lena suddenly being in a relationship.
With Alison, Louise, Axel and Seymour there's bound to be different levels of jealousy, moodiness or attempts to lure the partners away from each other. With Cindy, Mike and Minerva there's the cheating that complicates things, even if it doesn't directly involve the other part in the Ian/Lena relationship. Ian/Emma is probably the only relationship where all three parties will be totally fine with the current arrangements (if Ian/Lena aren't exclusive). But even in Emma's case there's the link to Perry that complicates things.
Add in the fact that both of them already had the chance to cheat directly after their relationship talk. Will they admit that to each other in one or both of the relationship scenarios, and will they be open about the other affairs they've already established? And how will Ian's slightly cuckish voyeur trait and Lena's exhibitionism—and her kinky fascination with the cheating aspect of her relationship with Mike—affect it all?
In every encounter between Lena and Ian, we're also limited to controlling how one of them acts. That's probably going to be a lot more difficult to handle for Eva from now on, as it's likely that they will have more serious issues to discuss if they're in a relationship (and continue sleeping around). We saw an example of that with Lena's response in the relationship talk, based not on any actual choices from the player in that situation, but on all the previous choices Lena's made in the past. That didn't seem complicated, because it worked so well and felt so organic, but I suspect it takes a lot of time to construct those scenes to account for all scenarios and how the players might see their versions of Ian and Lena.
I suspect Eva will use Jeremy and Ivy as conversation partners to help establish what ideas Ian and Lena have about the relationship; they've already been used in similar ways several times in the past. That in itself is rather funny, as they're both terrible at giving relationship advice, and they more or less only want Ian and Lena to sleep around as much as possible. But realistically that could help move the Ian/Lena relationship forward a lot in the coming updates.
Completely hypothetical conversation to illustrate the point:
Jeremy: So you're saying you're in an open relationship? And what kind of rules does that include?
Ian: Yeah… We didn't really discuss any rules, only that we wanted to experiment together…
Jeremy: Experiment together? So like threesomes, or that you're both free to sleep around?
Ian: Threesomes / Sleep around / Both, I guess…
Jeremy: Alright, high five! So you wouldn't care if she slept with that ex you told me she were meeting?
Ian: No, that would not be okay / I wouldn't like it, but I guess she's allowed if she really wants / That's the point, we're free to do whatever we want
Jeremy: Hey, man… So you wouldn't mind if I made a move? Lena's so hot, I have to admit I've been dreaming about fucking her myself…
Ian: Fuck you, Jeremy [grapples him to the ground and leaves him weeping in the street] / Fine, but only if I get to sleep with Louise / Hell yeah! Just make sure you're filming everything. I'm gonna have a jerk-off-marathon while watching it. / Only if I'm present! Eskimo brothers, amiright?!? [Ian and Jeremy high fives, strikes their chests and starts singing a new Eskimo Brothers chant they're improvising, pulls out their cocks and starts jerking each other off]
And then, when Lena and Ian meet next, and let's say Lena has the chance to propose a threesome or admit that she slept with Axel, the game has already set the variables for how Ian will react.