you are posting and venting your spleen because you may have been hurt in the past, each story is different and comes with different circumstances
Think about this statement. Look at the double standard you've applied here.
You dismiss the posts you dislike as people 'venting their spleen' and assign a reason to what you perceive as the posters anger. You decide that they (posters) are all wronged wives and so can be ignored/dismissed as not being objective and not seeing the nuance in your very, special and unique circumstances. You tar them all with the same brush.
Yet you then expect those same posters you dismissed with a stroke of your tar brush to not tar you with the same brush as every other OW, but to appreciate that each story is different and comes with different circumstances
You are the one who came on here asking how to change. Yet when people start to explore your thinking/beliefs (which is causing your actions) you baulk and question their credentials to judge you. Posters here don't have to give you any credentials. You asked for help and hard as this seems for you to believe this is the beginning of your journey out of these circumstances.
The journey starts with hard truths. Because until you forget your ego and learn about your own bias you won't be able to see the affair for what it is and you won't be able to stop it.
You mention the physical attraction between you more than once. You seem to be focused on that inparticular and you seem to believe this is a rare thing. It's not though is it. It's not hard to find mind blowing sex with any number of people. Millions in fact.
I also think that you like to believe that you have chosen this part-time-lover schtick as you are the one in control and it suited you but somewhere else you mention that you get together 2 or 3 times a week when circumstances allow. So you're just fitting it in when schedules allow, like everyone really. You want to feel you are a slick handler of him when really that's not the case. If you were really in control and just wanted sex at your convenience you'd have someone who was always available.
The point of all this armchair psychology is you are framing things to fit with a fantasy in your head. But there seems to be a lot of disparity between the way you describe them to yourself and then unwittingly reveal at other times are not so.
As I said CBT will help you get to the truth of all this and why you are making half arsed shitty choices. Once you understand that you can start to really change.