Would y’all have left

I’ve been with my NOW ex for the past 2 1/2 years and last week he did the most childish stuff ever and I’m still pissed. One day last week I took my daughter (with someone else) and his son who are both 4 years old to the park by our apartment and I notice a man walking around the park looking at me so I tell the kids they have 5 more minutes to play then we’re leaving that’s when the man grabs my ex’s son and tries to run off with him so I start yelling and jump on the mans back and starts clawing at his eyes so he drops him and runs off . Someone else had already called the police and i called my ex telling him what happened . Fast fwd to yesterday and he tells me he set that up because he wanted to see if I saw his kid as my own and I’m like are you serious and he’s like yea I’m sorry I was gonna propose and he showed me a big ring and he’s like I know I messed up and I’m like u right and we broke up .

Ofcourse there was more conversation but that’s summed up

Was I wrong for leaving ? What would y’all have done ?