I think there is more than I have wanted to admit about not wanting people to know about all of this. It is just such a sad, f-ing cliche to have my 40 year old H go and leave me for a much younger woman. I'm really, really angry about that. I think I need to better understand why I'm so much angrier over the actual leaving than the cheating. I can't explain it, but it is true.
What has your IC said about this? What do you think that anger stems from? In my previous M, I kept a lot of things under wraps about what was going on (alcoholism/abuse), because I was both angry at him for misleading me about who he was and embarrassed for me; embarrassed that I made a bad life investment, concerned it'd reflect poorly on me - but ultimately, it actually had nothing to do with me, and I think that is the case here. You have every right to be angry. Just know that it's OK to feel that way, and that his actions are a reflection of him, not you. You aren't defective. I don't get the vibe that you feel that way, but wanted to chime in just in case. Maybe anger because you now have to change the future you'd envisioned for yourself, and that isn't fun? You are having to mourn all kinds of things right now.
My heart goes out to you. I know this is hard, and I am sorry that H isn't making it any easier.