Child’s father beat up guy I talk to

Something so terrible just happened to me and I don’t know what to do! I invited a guy over and we was just talking in his car. I went inside the house to check on my son while he was sleeping and came back out to see my child’s father standing at his car door. I really couldn’t hear what was being said all I heard was “get the fuck on” and heard a lot of noise. Then I seen the guy swerving in the driveway and yard. I was so scared. My child’s father then called me and started saying stuff like why you doing this and am I trying to retaliate. Then he said he beat the guy up. It just really hurts me because I’ve moved on. Why can’t I do what I want and date other guys without him having to be a fool!