I get that you really like this development in NTR games, but you should probably give up hope of seeing it in Marina.
I've got a pretty good feel of the author's personality from all his works, and I'm more or less certain that he has no intention of turning the Marina series into full on NTR. These days that writer occasionally does do a proper NTR game where the heroine genuinely betrays the protag and leaves him for the other guy. But his main focus is on NTR where the heroine stays with protag in the end, even if she indulges in great sex with another man and is tempted by him. The majority of all the games he's written since that first
full NTR confession to netorase game he did have been like that. Though it has varied a little in whether the heroine still loves the protag and ends the affair, or if she carries on the affair while only staying with the protag out of loyalty and obligation, in the case of the Marina games and
this one the author has been very much focused on the theme of portraying a situation where a man can have a netorare fetish and still be happily married without it ruining things. With Marina especially he wants to show a situation where the wife will be both loyal and loving, understanding and accepting his fetish while willingly indulging in sex with other men without it ruining or endangering their marriage or causing her to ever consider choosing another man over him, even if some part of that loyalty might be due to having a happy marriage and family with the protag already. This is probably the ideal situation the author would like for himself in real life, so I seriously doubt he's going to let Marina have a real affair or even consider betraying the husband for real, let alone all the stuff you described.
Just go back and play the first two and you'll notice that the author is very thorough in having Marina never once take the initiative in the netorase except slightly when she is acting the part to excite the protag or teasing him in revenge after he tricked her into doing something she might not normally have agreed to. Both times he instigates the netorase with Hiroto and the Ex-AV actor, to the very end she made it clear she would be happy if he changed his mind and gave up any time. And when she finds out how amazing AV guy is in bed she even strongly urges the protag to find someone else. Her character has been steady and devoted to her marriage from the very start, even if she does enjoy the sex and admits that the netorase feels good for her.
I'll bet good money that even when game 3 comes along and it likely turns out to be the oji-san ex from her youth, it'll still end the same way. If I'm going to hope for anything I'll hope that the netorase escalates just a little further, even just a little bit out of the protag's control would be good. For example if the protag gives Marina a free licence to see the other guy and have sex with him of her own intiative whenever she wants, and she goes along with it, does it with him without the protag's knowledge and surprises him with her confession that did it with the guy that afternoon or something. Even if she only does it to play along with the protag's fetish, it would still be great. So long as it's just a little unpredictable and out of the protag's complete control without him knowing about every occurrence and giving his permission in advance, with just a hint more danger than there has been in the previous ones, I'd be very happy to see it. I hope the author can at least give us that much. If he's willing to take it a little further and let Marina actually recall some real feelings for the other guy and get in a little too deep before pulling back to protect her marriage, that would be even better.
Anything but the same exact formula, please.
