Tell Gabe that "We need to partner to get ourselves financially on track. I cannot and will not continue to do it alone. It doesn't work and it isn't good for either of us. I'm sorry I haven't given you a chance to be a real partner. What are your ideas?"
If he will not act like your partner, you can at least treat him like a tennant and your child's father rather than a child himself: "Gabe, I'm afraid I can't keep letting you slide on child support, my finances can't handle it. By my calculations you owe x.xx. Please start making regular payments on time and include a portion of the debt. Also, we need to come to an agreement on your portion of the rent and utilities. This is the budget I worked up..."
But, I'd give him a chance to work WITH you first. I haven't seen ANYWHERE that you have done so. It sounds like you showed him you were broke and he said too bad. When did you ask him to participate in building financial stability for your family?
