Good luck with tkd. my brother was an enthusiast.
Re running with the Mr. I was the first to run, and of course, when Mr. took it up, there was no contest. He could immediately go further and faster with less effort. (And before I had a Mr., I had a big brother who could always do things better and faster than I, snarl, grizzle.)
But one of the things that running keeps on teaching me is patience. I ran a 10K a week ago. Couldn't keep up with the pack for even 50 yards. But I didn't have to stop, and I was not last or even second to last.
I was immensely chuffed to have done it, and certainly enjoyed it, not even dead legs could take away the pleasure in the day.
I struggle, and I sometimes progress, but struggle or progress, I fit a great deal more comfortably in my own skin for making the effort to try.
Those who find it easy, if there are any, may be missing out on some of the best benefits of running.
Keep on at it. You can take solid credit in every step.