Well, RMS, I'm just a hick Okie, but I think going to Europe is the best thing you can do. Your marriage depends on it. If you give up now, your husband will bond with another woman and you'll find yourself divorced immediately upon his return. Patience doesn't seem to be his long suit.
It seems to me your husband steadfastly refuses to communicate with you. It is not your fault he "needs more." That comes from his immaturity. Don't let him browbeat you and don't let him convince you the marriage is failing through your shortcomings. He needs a major dose of "open up, communicate and learn sincerety." Only you can give that to him. The other lady can't! "I'm getting something from her you can't give me..." is just pure, unadulterated horse shit!
Become an independent woman right now! Take care of your life yourself. Become enthusiastic about the "open marriage" idea. Think of how much fun you can have. I envision you seated next to a handsome man on the flight to Frankfurt, pausing to talk to him for several minutes and jotting down his name and "anruf nummer" before passing through customs to meet your waiting husband.
"Who the hell was that?"
"Oh, just a guy I sat next to on the plane. He wants to give me a tour of the area around here." Kiss your husband deeply and tell him how happy your are to see him. Smile and wave "goodbye" to your seat-mate. Watch your husband's face.
I'm pleased you are on your way to learning German. It will make a world of difference in how you enjoy Europe. Don't spend much time on base. Get out into Germany. It will only take a few hours of study to be better at the language than 90% of the GIs, your husband included. Do that before you leave, please!
I can't wait to hear about your first "Open Marriage" affair! Go get 'em, Sexy Lady! flamethrow
Mr. Alura