Get involved with your church, perhaps.
find all the stuff you love about life …. the forest … walks in the park, museums, the ocean … and start doing them. As you do them you will feel the life you seek. *sorry for your loss
I'm kinda in the same boat.. except my wife decided she's a lesbian.. and I'm only 38. But I've been married since high school. What I did is went on a couple dating sites (the free ones) and went on a couple dates a week. I've made friends with a few cool ladies and I'm enjoying being single now.