Not really sure if you want to settle in here with a full thread or just wanting some advice...
It's often indicated that an affair really is a symptom of a deeper issue, so even though your W's A with her boss might be slowing, she might pick up another A with someone else...
My W has had three EA's for sure and possible two of those were PA's... she may or may not be "slowing" on her current A... or it is as involved as it ever will be...
Anyhow, the point is, until she begins dealing with whatever it is that was causing her to seek an A or is actually working on things with you, there will be risk...
Clinging to her to prevent her from being able to have an A will likely only drive her further away from you and go deeper under cover with an A...
Worrying about her having too much space and "leash to hang herself with" is pointless... she will continue or have further A's regardless...
Next thing to be clear about is, DO NOT compare yourself nor compete with the OP (other person / affair partner / alienator)... more often the WAS "affairs down"... even if the OP appears to be of higher stature, there's something wrong with an OP who will date or otherwise have an A with a married person... it's an affair down...
In the mean time, while you are not competing with the OP, what you do want to do is become the best that you can be, so much so that it becomes the "new normal" for you... dressing well when going on a parts run, keeping yourself well groomed, eating healthier, maybe working out... and having a great attitude about life, the universe, and everything...
Become a man that only a fool would leave... your W will not want to be a fool... but if she is... do you want to be M to a fool...?
If you want to hang with her and can emotional handle it and you stay in line with Sandi's DO / DON'T DO list... then by all means... hang out with her from time to time...
BUT NOT EVERY TIME!
You need to have a bit of mystery in the sense that, you should not always make yourself available... maybe take her up on her offer only 50% of the time and the other times, you have plans... even if you don't, if she invites you over tell her you have plans, and then go and do something!
In that way, you are not pursuing her, you are getting a life and enjoying yourself and growing as a person, and the onus will be on her to pursue... of course, you should let yourself get "caught" every once in a while, otherwise if you are way to unavailable and "out of her league" she may accept that she will never catch you...
It's a fine line and dance, but it's not much different than life before your W, when the two of you were courting...
But if you don't work on yourself, then if you ever to reconcile, how would your M be any different... or better...?