Is my boyfriend being possessive obsessive and manipulating me?

I didn’t think much of it but now I do. Yesterday me and my boyfriend were flirting with each other through text when out of nowhere he said “if I can’t have you no one can so I might as well just kill u 😙” with that emoji. I was uncomfortable but I laughed it off though none of my precious exs jokes like that with me. Today too he was telling me how much he loves me then he said “you better not ever leave me you’ll regret it you’ll never find anyone as good as me” and he said I’m the only thing that has been keeping him alive. Should I leave him? I’m getting really worried

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I meant previous* not precious exs whoops! Sorry about the spelling error!
Is my boyfriend being possessive obsessive and manipulating me?
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