i don't believe our S fall out of love, i think they just loose the feeling in the muddle of feelings they have. They mis-interpret everything and they come to a conclusion that helps them justify their actions. As they travel through the process they begin to interpret their feelings differently and come to a different conclusion, hopefully this is when they realise that they have love with us the LBS.
This is good but one thing that needs to be said is that the trip can be verrrry longggg. I believe that my H started his journey at least 2 years before the bomb drop and he has been gone 20 months now with no signs of any change in attitude. Having an om/ow gives them the intoxicating feeling of being "in love" and it is near to impossible for them to pull away from it. This does not happen because they are truly in love with op but because they love the feelling (the sort of high) that they get from it.
SH, First thing to get is to get the financials of the situation straightened out so you and you kids are protected. I guess when you talk to your children, because they are relatively young, give them only what they need and can stand to hear. No one has to be to blame to them, even though you feel differently. There is nothing to be gained by making one of you look like the "bad person". No matter what happens in the future, you will both always be these children's parents.
If you can, try to stop snooping, because nothing is gained by doing it and you get yourself hurt over and over again. Start GAL and work on improvements that you want to make to yourself. Spend quality time with the kids and do things with them as they are relying on you right now to keep a stable, loving place for them to come home to. I know it is hard but this needs to be your focus right now. Let you W swing in the wind for awhile as there is nothing you can do to change her. It is her journey, and she has not invited you along.
Be sure to read the MLC Resourses at the start of this forum and keep reading and posting. Sometimes just getting things out make them easier to live with.