KIDS KIDS KIDS 

I was in a situation like yours. I was married for 33 years. My ex cheated a long time ago and I thought we had worked it out. Well, he just learned to hide it better. He cheated all the time but I didn't know it. The last 10 years he worked overseas. I seldom saw him. He made a new life for himself and forgot to tell me. He married someone else in 05 and we divorced in 07.
I was the one who had to tell our daughter I was divorcing her father. As she was in her late 20's I told her the reason. She replied that she always knew something was not right and she didn't fault me for getting the divorce.
So no matter how good an actor you are or even that you don't totally know what is wrong in your marriage. Your kids know. We get caught up in the daily routine of our lives and don't always see what is in front of our faces. But the kids know. It's hard to hide the resentment and hurt when your spouse is cheating. Some how that comes thru to our children. So they think that is what marriage is all about when it shouldn't be like that.
You've pretended everything is okay since Feb 07. I did that since June of 2004. It wasn't easy and got impossible. I didn't like the person I was becoming. I finally made the decision to get out and wish I had done it sooner.
These are just my thoughts on staying in a cheating relationship. The decision is yours. You have to do what is right for you.
Take care and good luck

I'm one who do the leaving and I have 2 children... this is such a personal choice and there are friendly arguments from both sides of the fence here at D360 on this one. I think it's admirable to work hard on a marriage for the sake of the children. What I do not think is admirable is to just stay in the same unhappy marriage for them. If you are both looking at the problems and working on them then yes, great! If not... you are not fooling anyone no matter how wonderful your acting skills are... especially your children. What you are teaching them is a lack of boundaries and value to ones own self. You are in essence telling them this situation is OK. Is that what you want for them when they are grown? If it were one of your children in your shoes would you be ok with that? I decided I wouldn't and so I left. If it's not good enough for them then it's not good enough for you. They learn not what we tell them but what we model to them. Again, not to say you aren't doing what is best for you, it's just a different opinion.

everyone with kids has to come to this decision about stay or go on their own.  it's hard.  i am (was) a big believer in staying....(unless there is abuse).

but this site, and the members here, have shown me over and over again that our kids will pick up on it.  they will learn the cheating and the lying and the acting.

many people have said this much better than i will.....but something along the lines of....are they learning what real love and marriage is all about?

at the time of my divorce (he left me), i said over and over again that i would have stayed married forever..no matter what...for the kids.

now i can honestly say i wouldn't have...if i had been given the choice. 

has it been easy? nope.

but at least now my kids have a chance to see what a real relationship means....(that is if i ever have one again.....)

but at least they don't see the apathy and learn how to disrespect marriage.