Hey there - I haven't posted here before, but hello!
I'd agree with Amanda - you don't need an exit strategy. And as Mama Bear said, you can still offer, and no way will a child nurse when he doesn't want to. I'm still nursing Anna who is 3.5. She nurses at night before bed, and before naps on the weekends. She sometimes asks to nurse in the am and sometimes she doesn't. When Anna was under two, I didn't need to "offer" ever! Her requests were frequent enough. I do find I offer routinely before bed b/c that's part of our routine. If you keep offering, you'll find he'll either turn you down or accept. And that way, it's child-led. Enjoy it as long as you are both happy nursing.