Hubs, if you guys can tighten both your belts and do this without changing much other than simplifying life, that is the easiest way to do it. Also, stop thinking of this situation as two belts to tighten. You guys need to be a one belt team. All in or all out. Playing middle ground on this won't work.
Write a budget tonight. Start redlining current expenditures. If it looks too dire, then one or both needs to get side work at least short term until she finds a new career with more money involved. She can always go back to what she loves once stuff is under control, but leaving a loved job to a higher paying job is probably the easiest and most effective "sacrifice" you guys will make in this process.
The absolute most important thing here, for short term and long term, is to stop looking at this as two ppl and start looking at it as one budget.
Edit: after reading more, she def needs to find another gig if she isn't paid well and expected to work 7 days a week. eff that(on multiple levels).