The time I went on a blind double date with my ex’s SIL, my ex, and her husband… WWYD?

For purposes of this story, my ex’s name is Hannah, her husband is Jeremy and her sister is Amanda (all fake names).
Hannah and I started dating in our senior year of high school. It was great, but lasted about 6 months and ended things about a month before graduation. We kept in scarce contact until about the end of the year when I moved out of state. We didn’t talk at all for a couple of years but I knew she had started dating and ultimately married another guy from my facebook feed. When I moved back to our home state, I randomly got a message from Hannah asking if I still liked the same type of stuff. I said I did, and she replied that she knew a girl, Amanda, that “would be perfect for me” and offered to go on a double date. I said ok and then she said that it is her sister-in-law. I feel incredibly awkward at this point (I was 21 and not the best in awkward situations) because I already agreed but would rather not go out with her SIL, I had thought it was going to be a friend or something.
So the day of the date comes and I meet Jeremy, Hannah, and Amanda to go see some Christmas lights. Jeremy and Hannah walk off and I’m left alone with Amanda which was the “best” part of the date, only because that’s when I was the least awkward, but they come back and spend most of the date with Amanda and I. It wasn’t a great date by any means (mostly due to me). I felt like I couldn’t talk to Amanda with them there. Jeremy and I didn’t have anything in common that I could glean from the conversations that I had heard whilst on the date, and I felt like I couldn’t talk with Hannah (even though I had no feelings for her at this point, being married and all. I just got along with her best) because that would probably just upset Jeremy and Amanda. Then Hannah and Jeremy offer for everyone to come back to their place for hot chocolate any more conversation, and me being me, agree to go over. More awkwardness ensues and after a bit, I say I better get going and leave for home and finally get to unwind from that shitstorm of awkwardness that just engulfed me those last few hours.
So, yeah, that’s the story of how I went on a blind double-date with my ex’s SIL, my ex, and her husband (and in case it isn’t clear; husband and SIL are siblings).
P.S. During the time we were dating, I knew that Hannah’s parents were divorced and she lived with her mom 100%. What I didn’t know until after the date was that Jeremy had also lived with a single parent (his dad) and that Hannah and Jeremy’s parents married each other (after Hannah and Jeremy were married, not before).
P.P.S. So I guess, technically, I should have titled this: The time I went on a blind double date with my ex’s SIL/step-sister, my ex, and her husband/step-brother. LOL tricky stuff…

What would you have done?