Would you stand for this?!

My SO and I have been fighting a lot lately and both last night and this morning he said blatant threats to me like: "if this is how our relationship is going to be then..." and I always say "then what?" (Because I hate threats.) He just says "I dunno." He also said "you'll be f***ing miserable" as his answer. He denies the threats but as someone coming from a previously abusive relationship, I know ALL of the little signs of manipulation. Would any of you take this or would you speak up? Or walk out? What the heck do I say? I haven't spoken or texted him since he texted this long message to me lecturing me on the basic fundamentals of a healthy relationship this morning after our fight. Um what??