Just to add... if you have been unhappy in your marital relationship for a while, the affair just triggered more doubts (since you were able to compare). But, as the good old saying implies, apples should be compared to apples... Meaning, new adventurous relationship sparkling with passion is a totally different thing than a long-standing marital relationship where you're all settled down. Remember this when executing the "Line 3" in your plan.
Also... I'm a bit surprised you found it necessary to have the "Line 5". I would say, if you think "Line 5" is really needed -- put even more emphasis on "Line 3".
Other than that, all the best to you, so that everything that's happening with you now would only turn to the best for the future.