XH had started to look back. He started contacting you and then asks for forgiveness. Because ow's are very insecure she snoops and finds out. ow is very upset.
XH backpedals trying to convince her that it's not what it seems. XH takes ow out to dinner to show her all is well. ow is still PO and XH is still trying to convince her. You happen to come into the same restaurant and innocently go up to them while they're having a discussion about you. To prove to ow that there is nothing going on, he verbally attacks you.
I know you have no idea if it happened like this and will probably never know. At least it would explain how your XH could be so stupid as to verbally attack and threaten you when you were with your brothers and your Dad who would have just as gladly kicked his butt in your defense.
No matter what was going on, XH was not too bright to say those things to you. I'm sure since you haven't answered him when he's tried to contact you, he's got the idea that it wasn't the smartest thing he's ever done, and is trying to atone for it by sending you money. He may be trying to get you to talk to him again and sent it with no explanation so you'd contact him and ask about it. My H has used that kind of tactic before.