3rdstrike
This from someone who grew older in a poisonous home environment
I knew both parents were capable of teaching alley cats mating lessons. It sucks when you haven't reached puberty and can see that "mommee & daddee" are "with other persons of the opposite sex" even though you don't know all that such liaison implies.
Teenagers? They KNOW what has been going on - or the very least are all but certain something really serious is going down.
Unless they hate both of you - they will be sad, more than likely very sad and also ANGRY!
Dissolution of the marriage/home is a HUGE change for them bringing a forced on them new experience that is, at the least, very unpleasant.
Both DD are dependent on you and wife to provide them a living environment without strife and unknown future. Starting a divorce is to destroy that environment.
I am not intending you to be shamed into any action for which you have decided you must execute. Whatever path you follow - it is your choice to make.
What I suggest is to separate, yes start the divorce proceedings, but note that final decree is is somewhere in the future. See what passage of time does to your memories and thoughts. With enough passage of time, the pain will soften.
I went looking for your "story" and found it (yay Google) and you posted that you were pretty much a total loser for 4 years (my choice of words for what you wrote) and also emotionally removed from being a father for longer - way longer.
After reading your earlier post, I am thinking your wife has lost respect for you as WELL AS love. Stop and think, WHO likes an alcoholic?
Well, drinking buddies!! aka another alcoholic.
She is (in a bad way or choice of words) asking you to stay and I am guessing "for the DDs" and maybe hoping the spark that brought you two together years ago can be rekindled.
BOTH OF YOU have a ton of SXXXy memories to learn to live with before that can happen.
Consider also you are tied to her in some way by your two DDs for life.
You will NEVER be able to stifle the memories.
You will learn to live with them or die trying.
Keep in mind everything you do that the two DDs can see is a memory for them - for life.
Tell the DDs what you intend to do with as gentle words you can muster - but tell them the truth.
"Take from my words anything that may help and toss any that with which you disagree."
peace