Its easy in the first steps of DB to blame yourself for it all, I know I did it.
It really takes 2 to ruin a marriage, I think that's the biggest take away for Jake here. He has flaws to work on and so does she. The catch though is that as Mr Bond, 25, and myself know, he can only directly change himself.
So Jake focus on fixing your flaws first, you may have been a jerk, you may have been a doormat, you may have been some mixture of both. Change to make yourself a better person, then as you change are a better man, and establish the boundaries you need she will be faced with deciding whether she wants to do the hard work to stay with Jake 2.0 or leave.
The old Jake landed you in a possible affair situation, time to try something new. Be the type of loving husband any woman would be dumb losing, AND be the strong man that will not take disrespect from his spouse.
I see 2 scenarios for you
A. You were a lousy husband so she had no incentive to stay.
B. She has so little respect for you that despite being a good man, she knows she has you like an obedient puppy, and sees no risk of losing you even if she gets caught.
The truth is probably somewhere in between, regardless its time to roll up those sleeves and start working. BTW have you read [edited by dbmod: reference not recommended nor allowed] yet?