IB, I agree w/all of the posters that have posted to you. It takes time to regain the capacity for joy. You've had several whammies in the last few months, i.e., daughter gets married, son moves to college, you moved out of your home, etc. All of this kept your focus off of you and how you feel. Now, w/the sudden quietness, you are feeling the losses and yes, it's going to take time to get your feet planted again on firm ground, but you will do it.
Give yourself the gift of time. It going to take you a while to figure out what you want to do, but I promise you, what you are feeling right now will gradually disappear and when you least expect it, you will begin to notice the sun is shining, the birds chirping and the flowers are beautiful.
You have been extremely hard on yourself and there was absolutely nothing you could have done about your h's crisis. It is his to own all by his lonesome. As for the house, you did the right thing by walking away. You would never have pleased him because he doesn't know what he wants in the way of life.
IB, make a list of things that you would love to do, but haven't attempted them. It's time to start w/one little project and work yourself up to the larger ones when you are ready.
I'm sending you positive vibes and hugs!
Sit quietly, the answers will reveal themselves when you least expect them to. The past is gone, the present is a gift and you need to focus on today, allow the future to reveal itself when it is ready.