Hang tough big guy.
Don't let the ex-beach's actions elevate your stress level. Stress is certainly no good for you right now.
Glad to hear your eldest daughter is ready to do the right thing for her siblings. She sounds like a great kid.

This heart stuff is very scary, but the medical profession has learned some incredible tricks to get you back up & running.
I'm sure they will get you walking soon.
Enroll in & start participating in a Cardiac Rehab program as soon as you can. The peer support in these programs make an incredible difference in your view of your future and all the important stuff.