We've got an allotment next to a fairly busy road. There's no direct access to the road, it's about a 200m walk down two paths.
My partner was meant to be looking after our 2 year old while I went home to get a coat. When I came back about 15 minutes later our toddler was at the side of the road, on his own. He'd left the allotment, and apparently my partner thought he'd stay nearby so didn't follow him. My partner didn't know I was with him. He didn't show up at the road side for maybe three minutes, didn't seem upset, didn't apologise. He said later that he'd been really worried and just hadn't shown it. I'm feeling furious and disconnected and just generally full of dread and he doesn't seem to get why. I kinda think it's obvious but that's not getting us anywhere. Am I overreacting? Any advice?