Why not get on the internet and find some cheesy silly jokes to remember. You both can laugh at the ridiculousness and it might settle down your nerves.
I have had the same issue with approaching women or talking with people. I felt I needed to be charming or serious or have a point to the conversation. I don't think so anymore. I have had more enjoyable conversations about the most random of topics than things I thought were good topics. The joke thing has worked for me with just about anyone I talk with.
Being with your W as long as you have you can probably think of something she likes. Ask her questions about current events that are in the news, then follow up with questions about what she said. I find it easier to ask questions and listen than to talk. Becoming a better listener and using my heart instead of my ears has helped me become better at conversations.
You seem to do a lot of traveling, I am sure you could find things to talk about. Airline food, flight delays, turbulence. I also make up ridiculous stories and make obvious lies about things just to be funny and have something to talk about. Upon leaving or returning from a flight I might talk about how "I am nervous to fly again because last time I had to take the controls while the pilot used the bathroom. He got the kosher meal, but it must not have been any good. Those new 777s are a little complicated, but nothing for good ol' me to figure out. With a little help from Google I had us on approach to JFK in no time."
Seriously, try the stupid joke. For example.. "What did the fish say when he swam into the wall? Dam!" No need to be embarrassed if it doesn't work, after all the joke is supposed to be bad in the first place. Break the ice and start talking.
M:34 XW:34 Together: 10y Living: 9y Married: 7y Son:6 Son:4 Separated: 12/28/13 Piecing: 5/2/14 Separated 2nd: 10/16/14 W filed, but pulled it: 11/5/14 papers served: 1/27/15 D final: 3/6/15