Cinders... Forget about whether the label of MLC is accurate or not. Just know that your H's behavior is not healthy. Healthy people don't allow a third person into their marriage. They don't walk around thinking they deserve this, and they don't walk around blinded to the fact that they are causing hurt to their family, even their own children! Don't buy into his reality. Remember that you are choosing not to go ahead and divorce your H, but you must think of him as gone, and move ahead in your own happiness, for yourself, and for your kids. That is your journey, and it's not a bad thing to learn, how to care for yourself in times of stress. You can do this!