SL, Do you want to save your marriage? Do you want to work things out with your W? These are two huge questions you have to ask yourself. If you say yes to these, I would advise against being with OW right now and focus on you and your kids. You have to figure out what made you miserable the last few years and make the changes to make your happier and better. OW can't do that. Only you can. I would also pick up a copy of DB and/or DR because they help tremendously on getting you started.
I am not that familiar with your sitch, but have you and your W tried counseling? I mean if you and she are willing, its a great first step to repairing your R and hopefully building a better and stronger one. But I don't feel you can do this by dividing your energy on OW. Its better to take this time to focus on you.
