I've got a decent job making ~$60,000 per year, but it's keeping me crazy busy at the moment without much free time or mental capacity for other projects.

I came from a family raised with the “poor man” mentality which is to get a good education, get a good paying job, and retire at 55 or 60 years old.

What is the opportunity cost of your mental capital?

You have to be mentally ready to “let it go” if you proceed here.

We're starting out under a "do it right, do it now" type of mentality, so it's good to hear from someone that's familiar with this process that we're on the right path!

He has mentally sold and is ready to move on.

I think we are just so used to getting no said to us and our egos crushed through all of our training that it gives us the mentality to push or find creative solutions when others will give up. 

Basically, how do I mentally prepare myself for their potential moving?

This is a financial and mental disaster for us right now.

As long as you felt comfortable painting a mental picture of what the final product will look like.