I think these statistics are based off of how the WS is and was during the affair. Say dd hits and then everything is rugswept...or isn't fully addressed and the WS doesn't put in the effort, then there is a 100% chance of it happening again.
As of right now, I am POSITIVE that if my WH does not improve, he will have more affairs...it's a matter of when. The reason why I'm sticking around? To see if he does put more effort into looking inside of himself and getting his hands dirty. He says he is, but I'm getting more words than actions so far. He's smart....he's giving me JUST enough actions to keep me interested (or maybe i'm cynical). Also, I'm not in a rush to get in a relationship right now, my daughter is only 6 months and I would like help with her (and for them to bond while living together) and for me to get my shit together career wise. During that time, as I see (or hopefully see) improvement in this man, then I will lower the 'rate' for my own marriage.
He asks me if I still want to be married. I always tell him "The way things are now? HELL NO! If things get better and I start to feel like I can trust you? MAYBE. If i'm slowly seeing this transformation of yourself. You looking inside yourself and changing from the ugly fuzzy catepillar that I see now, to the beautiful butterfly that I know you can be (that I see hints of at times), then yes. And even then, I won't be 100% sure you won't cheat again, but at least that little percentage that is left will be worth the gamble THEN and ONLY then."
What has your WS done to show you different? If there really isn't anything substantial, you should have it in your head that it will most likely happen again and focus on yourself. Then reevaluate accordingly as time goes on so you aren't blindsided.
ETA. **Well, she's an IC, not a MC so I see her loyalty should be to YOU and not your marriage. Why would she counsel someone to stay in an unhealthy relationship? You only control yourself. That said, she may not know the work your spouse is doing.** I agree with this statement. MC is for the marriage, but the IC should be only thinking about your welfare...and if an IC was trying to push me to stay with a habitual, lying, disrespectful, cheating asshole who doesn't seem to know the truth if it bit him in the ass, then THAT is when I would be seeking a new IC. However, if you feel that the IC is condencending or berating you for thinking that what you want to do is save your marriage, then go for it. But I think your IC was just trying to show you the enormity of the situation and to show you that there is a chance that no matter what you do, it may not work.
Good luck either way.