Thanks for your post and description. You ask a question - ok if I ask one back?

Why avoid riding with him in the future? Was it awful? You were, if I've read right , the invitee.

Maybe, if you're a bit quicker but he's a nice fellow, how about a pre-ride itinerary agreement? " Let's do the first 20 together, then whoever's strong can do the xxxxxtown loop and we'll meet for coffee where we started"

I like and enjoy rides with both faster and slower pals