How many endings are there?
I've used the full save that you can get from this thread, but playing through from the beginning I can say that there are 4 endings so far, I wasn't in the mood to search for more if there are.
For anyone that is interested, there are 2 NTR endings and 2 not so happy bitter sweet ones.
The NTR is avoidable to a certain point but not completely, meaning that you can stop other sexual interactions from happening, but some will still happen regardless of what choice you choose. For example, when you "stand up" to your boss instead of tucking your tail between your legs and whimpering as your wife tries to save you, he will still grope/touch your wife as he leaves, what he does to your wife differs from either standing up for yourself or letting your wife save you, but it still happens.
The second example is when another coworker of yours somehow convinces your wife to give him a blowjob just because he "accidentally" exposed himself to her in the hot springs (I swear if the wife wasn't as hot as she is, I wouldn't be interested in her or the bimbo logic she comes up with, its typical NTR hentai 101 type logic at this point)
Its been a few days since I've gone through it all, I'm not 100% sure if you can stop her from getting blackmailed by your coworker or not, there is a choice where you either forgive your coworker for whatever the MC thinks he did to "embarrass" your wife or you can tell him to apologize to her.
Him apologizing to her means he will almost "accidentally" reveal what they did, in which case your wife will intervene and pull him aside for some "much need talk" about almost spilling the beans, another sexual interaction with them after the apologize choice.
If you mainly choose to stay with your wife, as in not leaving her alone to get molested, the only sexual interaction that happens is with the boss, but from what I've seen, you can avoid that from happening if you stay with her.
All in all, this is a very basic light NTR experience for anyone going through it, some sex scenes are hot due to the Wife and female coworker art, some are just so idiotic that it causes you to forget your playing an NTR game for a brief moment and scratch your head, but then you remember its an NTR game and then the logic makes sense for an NTR game.
The not so happy bitter sweet endings are where your wife gets a few small sexual interactions but you end up getting her home fine after hot springs trip, its anyone's guess if the wife continues down that rabbit hole of getting groped by other men but seeing as how easy she let everything happen, I'm sure we can all come to the conclusion that she is going behind the MC's back from time to time even if they don't show it.
The second is after your wife gets raped by the coworker and some other dudes he invited, you get a jealousy sex scene between the MC and his wife, I guess that ends with him becoming a willing cuck and forever locking him into finding other dudes to fuck his wife just so he can get off.