But I do have a final question for you folks. Do you think its possible or fair to bring around a spouse to Mustashian's living?
I think this is a really valid question. First, I want to commend the two of you for having such a productive, honest conversation - it can be difficult to do that with such a loaded topic, so kudos. That said, you mention surprise at such a quick turnaround in his willingness to share -- please be attentive and watch to see whether his actions line up with his proclamations. Look to someone's actions rather than statements to ascertain their values and character.
I think people contain a spectrum of who they are ... or, more accurately, we all have the potential to develop/evolve in many different ways. For instance, I'd say I'm pretty Mustachian now (objectively) - husband and I spend under 3K/month for the two of us, have about 100K in investments (at 25), plan to be FI by 40. And to a large extent, I've always been nerdy and into math and finances, which are the aspects of my personality to drive me to care about finances and analytically look at life. But I wasn't Mustachian in my prior years. I was reasonable and maxed out retirement accounts, but I also ate out a lot and didn't really think at all about optimizing my purchases, or aligning them to my values. But fundamentally I had the inclination and potential to go in this (Mustachian) direction.
So I think you need to figure out who your partner is, whether he's someone that is interested/capable/willing to learn about the lifestyle you have in mind. Talking about future goals will probably illuminate a lot of this. Good luck! :)