It occurred to me this morning that you probably haven't even shared any of the financial concerns with Gabe, that you haven't even given him a chance to respond to the situation appropriately, that you haven't given him space or opportunity to be a responsible partner.
So, it is time for you to woman up. Quit being the household's mother. You are Marc's mother, not Gabe's. Gabe is your equal and your partner. Treat him like that.
Right now you are treating him as if you are the parent and he is a kid who came home after college, a parent who wouldn't be doing that kid any favors, BTW, for allowing the existing patterns to go for so long.
Don't say you can't talk to Gabe. If you can't, then write him an email. If he doesn't read email, print him a letter. If he can't read, write up an email and have your computer read it aloud to him if you can't bring yourself to do it.
"Gabe, I ran some numbers, and financially things are much worse for us than I had realized. I'm stressed, I'm scared. Let's sit down this weekend and figure out a plan together to make us more financially sound than we are right now. Together I think we can make it work, be each other's rock. I'm thinking that we can partner to make a workable budget, and brainstorm on how to save money, maybe think of how to leverage our off-work hours to save money somehow. It won't be easy, but if we get some power over this money stuff, it will sure feel good."
BTW, sex will be much better if you quit parenting Gabe.
Also, if you google how to feed a family cheap, there are tons of sites:
