If you're trying to kick a habit, good or ill, or constrain it then it helps to have incentives that motivate you toward your preferred behavior. A grazer worried about their weight might tape a photo of a fat person to their fridge door, a smoker might post notes on lung cancer statistics next to their ashtray. I had a friend who was contemplating an affair with a coworker and ended up putting up the 'family photo' on her desk in the direction of the fellow's work area so she'd see that every time she looked temptation's way.

I'm not sure what your ideal here is, to be able to say if that is a good one or one that needs discarding or altering, but I'd actually write it out (then destroy it) and line up what you want, what you really actually want, along with the pros and cons, and then the various runner ups and their pros and cons and select the one that is the best cost-to-benefit ratio and has a high probability of being achievable. That sort of thing is only possible, or at least only useful, if you're capable of being brutally honest with yourself. Most people aren't but think they are, and in my experience if you come away feeling lots of self-justification or self-loathing you missed.

It is entirely possible your best solution is to just sit your wife down and tell her, truthfully and explicitly, what your problem is. Note by explicitly I don't mean gory detail or naming names which would probably be harmful and pointless, but rather in terms of motive and desire. She might have some good insights or solutions, alternatively if she blows it off in a fit of rage or refusal to discuss it as uncomfortable at the very least you'll have learned that she's maybe not quite as emotionally tough and realistic as you thought and maybe not a good choice for life partner. I wouldn't want to be married to someone who didn't think I ever contemplated other relationships anymore than I'd want a wife who said "Our son would never use drugs!" or some other such thing. Honesty and respect vital to relationships and all that, barring the general social contract of polite/necessary lies of course. So you might find out she's not the ideal long term partner and can act accordingly. But she might have some useful suggestions or insights.

That's about the best I can offer without more information that I frankly wouldn't advise you offering up, beyond the cliche but still wise "Don't". I will pitch that one for a moment though. Your situation may be different, I lack sufficient info, you probably think so but aren't a reliable observer, but odds are it isn't and the vast majority of the time no net positive will come from an affair. Consider discussing it with her, and try to find incentives that help you to follow your chosen path or avoid pitfalls. Good luck.