Having been powerfully tempted, I relate to this a lot more than I used to. I was being emotionally abused, and our sex life was extremely poor and stressful, and I felt unliked and undesired. I was convinced I loved her and that we could work through it, and she had excuses to explain everything, and I was complacent and scared of rocking the boat, and I didn't realize how fucked up it was - that's why I stayed.

Anyway, after about 4 years of being with her, someone I knew flirted with me during that relationship, and all that amazing high of being wanted, of being attracted to someone who reciprocates, of having fun flirting, etc nearly took me for a ride. In my relationship we were allowed to flirt and kiss others but no farther - but I knew in my heart she wouldn't actually ever be okay with that because she was very much the type to say things were fine when they weren't. I didn't kiss him, because I knew if I kissed him I wouldn't be able to help myself from going farther. I flirted hard, though, and probably crossed the line with it, despite the "hallpass." It's hard to describe the intense pull of it... the urge was POWERFUL. It took immense amounts of willpower not to cheat, with no prior intention/planing on my part. And it spurred me to have the last of many big discussions with my SO about our sex life and other problems. I broke up with her less than six months later. I'm glad I didn't go through with cheating, but it really changed how I perceive it. The whole "I didn't intend for this to happen" 'excuse' now makes a lot more sense to me - but also speaks of something seriously wrong with the relationship to begin with.