Cuck route: Don't choose cheating porn, Don't let Martin enter the bathroom, Visit the swinger neighbors but only let Anne have sex with them and kiss her. You will get the scene when Anne leaves her job and goes to the beach and you come home in the evening.
For the spa scene: you do the opposite except here also if you don't select cheating porn but take swinging porn instead and then go the cheating route. Let Martin enter the bathroom and have sex with Anne then visit the swinging neighbors but don't enter their house and when Anne tells you that she wants to enter tell her to stay she doesn't stay.(really wanted her to stay though).
Then on the same day as above one she goes to beach with Martin and then after he leaves flirt with the man on the beach aka Drake and he will invite you to the spa.
After a few playthroughs this is what I got the last time.
I chose interracial swinger porn.
Met the swingers and just watched, afterwards kissed her.
Let Martin go in the bathroom and didn't intervene (I think...).
She fucked him at the beach, and afterwards stayed and met what's-his-name and had anal with him on the beach.
She then went with him at the spa and had the threesome.
But also told me about having anal at the spa with the other white guy (again forgot the name). Idk if this was another time she went to the spa, or is it a plot hole (because there are several others like that in the game, e.g. if she doesn't fuck Cornell, he's still mentioned on at least 2 different occasions, as if she fucked him, one is the night after when she gets the disappointing sex with the other guy and the other is I think when she fucks another black guy at home).
And also made me eat her pussy after she told me she fucked one or the other guy.
On a side note, I noticed during several playthroughs, that the day she stays at home and masturbates in bed, in most cases she fantasizes about swinging, but one time I got her to fantasize about Ryan, wishing he would come visit again, I think that was the cheating route, but I'm not sure.
Also one time at the end of chap10 when Ryan goes back they fuck, but afterwards she tells you about it, and doesn't fuck him the last night behind your back. Idk how I got that one, but it is possible. I mention it, because I've noticed that some people have the impression that no matter what you do she still cheats with him.