It very much depends on what the girl wants, what you want, and what kind of relationship you're in. Obviously, if you're actually sleeping with other women, you'll always have that mystique about you, and she'll never be able to completely tie you down... but, that may not be what you want, or you may not want to risk hurting her if you're promising her monogamy. You'll have to tweak it to your own situation. But, at minimum, have at least one other place you REALLY want to move to somewhere in the world where there are women you're excited about exploring, so you always know mentally you aren't option-less.
As far as higher degrees... nope, nothing of the sort. Just a Bachelor's of Science and that's it. I am considering a higher degree at some point though... like it or not, people care about credentials, and I'm starting to feel a little naked with my current set.