Keep your IT sales job and start flight training part time. Get your Private Pilot's License. Maybe even start instrument training. Then decide if you want to do it for a career. It's gonna be expensive, and pay is lousy for 2-3 years after getting your commercial pilot's license. But once you hit the magic 1500 hour mark and get the ATP rating things will start looking up.
Your going to have to either go into deep debt for flight training or use a lot of savings if you have that. It's a very long term payback thing. That's something you need to discuss with your fiance. You might even want to slow down and keep the sales job until obtaining your commercial pilot's license. Depends on your financial situation. Also, does your fiance have a decent paying job? See if she's OK with being the primary breadwinner until you get your time in. Show her that in the long run you'll make enough money that she could choose to be a stay-at-home Mom if you guys want kids.