[Wins88]

Your stressful job is reason number one for your inability to get excited unless put in a situation like outdoors sex or anything super exciting and thrilling.
To me, I feel you should be honest with ur GF about what thrills you.
Cos taking the next step n having a working n good marriage will require both parties to work at it.
I was divorced because I could not be honest with my 1st wife about matters regarding sex. I remarried, and was perfectly honest with my current wife about my sexual preferences for fetishes that excite me and until today I have enjoyed more than 18 years of good marriage and equally satisfying sex life (no need for FL etc) cos my wife knows what kind of freak I am and caters to it and eventually became a freak like me LMAO.
Honesty is the best way to start it and make the marriage last n happy.