Well I agree with Dawn. She gives very good advice. You can't tell H anything right now. Not about the debt, not about the OW. I know it hurts. You also can't get so angry with S's. I realize that it feels like they are choosing him over you, but they are just kids. They are very confused as well. S19 is showing definite irresponsible behavior, probably in part as a reaction to all of this. I had a friend who was killed by a drunk driver while in high school, so I hope he can really get some help. S16 sounds like he is doing well. He has a good focus and you need to help him keep that. You also need to focus on yourself. That is what is important now.
If you focus on the past, you ruin the future. You can only live for today.