This thread, Infidelity and BDSM does not make for a light reading, especially the further it gets, but it might be beneficial for both of you to read up about other peoples experiences as to better understand where the other side is coming from.
tommiecat you are the one who has to decide if you are willing to give this another shot, only you know if this is something you can eventually surpass - if its something you are even willing to work on. But do not let anyone pressure you into anything, whatever decision you make, its all right.
Mr. Tomcat, if she does give it another shot, you better be realistic and prepared for the fact that you will have to do a lot of reassuring and watching your steps so as not to find yourself in a suspicious position.
Love isn't perfect and neat - its messy.
R/L relationships are not romantic idylls - they require assurance of commitment and patience. Lots of patience and time.
I truly wish you both the best of luck.