I don't believe I have read any of your posts before, Lifeoutthere, as I am pretty new here but.....you sound well and content with your life and....life keeps going on both for your children and, most importantly, for you.
You have an invitation out to dinner with a FRIEND. It just so happens that your friend is male and if, in your new life, you want male friends, you can have male friends too. And you can forever be "just friends" if that is all YOU want.
XABF had this real problem with me having "just friends". It didn't stop him cruising the adult porn sites with a profile describing his ideal partner. He called this his "social life" and considered it harmless. He couldn't seem to get his head around the fact that I could also desire a harmless (but healthier) social life when we were apart.
Please don't let your XH's "quacking" influence the decisions you make now about YOUR life. He never had any control over you. You control you! You are making a success of your life and you need to keep taking the steps to more success.
Have fun at your dinner!
ARL