What if Perry is himself involved with Emma who belongs to the very same group and Ian and Emma have done things too? What if Ian is going Chad mode? IIRC Emma stated that she is quite kinky herself, will revelations than affect Emma's thinking about Ian? Things can take quite a turn.
Sure things can take a turn and I dont doubt that, but looking at Perry just as a character and his thoughts, my opinion is still that Perrys reaction is most likely to change due to the timing/circumstances of the reveal rather than your own actions towards him
...
So, if Ian and Cindy can continue this relationship without ever getting caught (which I think will be doable) and Cindy ends things with Wade, I would say that everyone including Wade would be "okay"with Ian and Cindy just "finding one another" a month or 2 after their breakup. They wouldnt be over the moon completely in the begining and most certainly Perry would always be suspicious about the whole circumstances, but still not mad
.
But if they get caught (lets say by Perry for the sake of argument) before Cindy ends things with Wade or way too soon after the breakup, in my opinion theres no way Perry isnt hating Ian right there and then
regardless of all the good choices or actions you have done towards him and regardless of you getting him in a relationship with Emma and if you done something with Emma or not... The betrayal would be just too severe to be outweighed by any of the other choices...
While other characters might change their opinion depending on your choices (like Lena), It just doesnt make sense to me based on Perrys character that he himself would... Maybe if you made all the right choices he forgives you and understands afterwards *shrug*