I don't buy it for one minute that You Started this.

He knew who you were for 3 years, then chose to ask for your hand in marriage. Marriage takes work and it's a partnership.

Of course you're feeling sui thoughts because it's a traumatic point in your life. The situation of having him here today gone the next or holding that over you IS TRAUMATIC!

At this point I find this threat of his abusive by itself.

If his parents continue to enable him then that sounds dysfunctional. I'd perhaps land behind bars if mine kept showing up at my doorstep. He doesn't sound properly "launched" which is supposed to be the goal for parents to launch their children from the nest into adulthood and independence.

Do you have family to reach out to?