Recommending R
I don't think there's ever a situation on SI that calls for recommending R or D. The best we can do is help someone figure out what they want and what is achievable, and/or confront people with the inconsistencies in their thinking, and/or share one's responses to what a member posts, and/or share one's experience.
Intentionality
...any human with a conscience will think through "isn't this wrong? Couldn't I hurt my wife/husband? What if they find out?"
Has no one here had the experience of doing something wrong, hurting someone close, and then realizing they should have known they would hurt someone before they committed the hurtful act?
People are not perfect. There are lots of threads to life and lots of threads to most decisions. It's easy to get caught up in a moment and lose track of some potentially important inputs into a decision - and the consequences of that can be catastrophic to one's own life and the lives of those who are in one's circle of influence.
Abuse?
I think the terms one uses affects one's thinking and behavior, and I think it's relatively easy to abuse 'abuse.'
The more energy a person puts into thinking in terms of abuse, the less energy is likely to be available for healing, IMO.
Calling infidelity 'abuse' mixes the focus up. The WS has one set of problems to solve. The BS has another set of problems. Healing requires focus on oneself. When 'abuse' is in the picture, the picture is about the effect of one person's actions on another, and that takes the focus away from the work that's needed for healing.
Further, if one sees oneself as 'abused,' it's too easy to fall into self-pity, and once in self-pity, it's hard to get out.
I think a much better metaphor for a BS to adopt is that of 'collateral damage.' That is, my partner fucked up, I've been dumped into a combo garbage dump and cesspool through no fault of your own, and I'm the only who one can get me out of this mess.
Sometimes one gets to choose the words one uses. When one has a choice, one might as well use the words that help most.
When one has work to do, it's better to choose words that give one the power to do the work, not the words that give power to someone else, one's abuse.
Sure, infidelity is abusive, by many (most? all?) definitions of 'abusive.' What implications will one draw from that fact?
Resentment
I get your point, stinger - sometimes (I think it's pretty often) a WS cheats out of resentment of the BS, and that is really hard for the BS to take - at first.
A little thought, however, reveals that the resentment is the WS's problem. It's not built up against the real BS. It's built up against some filtered view of the BS in the WS's head.