On the cuck route, it ultimately makes no difference who Lena cheats on Ian with. Because eventually he'll agree with everything anyway. Cucks basically want their partners to cheat on them. And the more humiliating it is for them, the more they secretly get a kick out of it.
With Axel it's all about getting her own back on him, by making him believe he has a chance with her, but all along being with someone else and fucking a load of other guys. Axel is ultra-possessive, and ultimately will get sucked in with Lena again. But with Ian as the perfect cuck and Seymour, Jeremy, Mike and others providing for all her needs, is he really getting set up to be dumped, just when he believes him and Lena can be an item again?
And Jeremy is just a boytoy who is really out of his depth. He's playing with fire doing the dirty on his best friend, and even more so because it totally contradicts his personal bro philosophy. But he was right all along about Lena on this route, she definitely isn't girlfriend material, unless you're a cuck of course, in which case she's perfect.
For me, the biggest problem will definitely be Seymour. He almost certainly wants to control Lena completely. He'll try to fuck up her relationship with Ian, cuck or not. He see's Lena as his ultimate possession, the brilliant diamond he just has to have. And eventually he won't want to share her with anybody. So at some point she's going to have to find a way to get rid of him. Hopefully, by then she'll be successful enough not to need him, or Ian will be a best selling author, and she can just live off him instead.
This is just the cuck route. And Lena is ruthless, nasty and a complete whore, but oh so sexy. You can play Ian and Lena very differently, and I do. On the open route, I have them both so far completely faithful to each other. But gradually moving towards a swinging lifestyle, and perhaps more. But whatever they do, it will be mutually agreed on ( definitely no cheating).
