Your children are not your parents, Ruby, as you are theirs. You don't need to discuss your problems with them.
Neither are they your "friends." They aren't people to turn to and unburden yourselves, etc.
You and dh have a cousellor. If that's not helping, you need to face whether or not you want to leave the marriage. If you and dh decide to split up, you'll have to let the kids know, of course. Even then, you don't have to tell them the whole story right away (it will probably come out eventually). They just need to know if the marriage is over, who's going to live where, etc. - things that affect them. That's all.