C.L.
I feel your pain. I just separated from my husband - but my husband was far from perfect, so the situation is different. I was no longer "in love" with my husband, and that's why I decided to separate. The kids go through alot and it's not always easy - but I'm happier and that reflects on how I manage the house, and therefore how my kids react to the situation. I've been fortunate in that my husband and I have been communicating better than ever, and he's even stepped up to the plate regarding the kids. I don't think we'll reconcile, but at least we're getting along.
I highly recommend counseling - you need to figure out what it is that you want and what will make you happy. Only you can decide that.
I wish you the best of luck in this most difficult decision.