How worried should I be about my exes ex deciding to get violent with me should our paths cross?

She told me he was obsessed with me, stalking my social media, insecure about his dick (He's like half my size. ~3.25" to my 6.5") accused her of still loving me (Which ain't false) and said that he's gonna fight me if he sees me. And has gotten physical with her

She left him, and we started talking again. And we both deleted our social media (Or at least the ones he knew of ours.)
He probably is convinced she did actually get back with me (We probably are getting back together soonish though, as more time passes after she left him)
How worried should I be about my exes ex deciding to get violent with me should our paths cross?
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