T is for Tricycle

On one of our first dates, Ex and I went to the roller derby. It was awesome. The crowd was excited, the bouts were fierce, and Ex was in fine form. He was animated - laughing and cheering. I was having the best time.
                   
At half-time, they asked for volunteers. Ex jumped up and ran down to center ring. I was elated. My boyfriend was brave, fearless, and energetic! Turns out, they wanted adults to race on huge tricycles in pairs, one pedaling and someone standing behind and holding their shoulders.

Ex waved me down. I'm not the kind of person to volunteer for something like that. I was quite content to stay in the stands and watch. But I went down happily, jumped on the back of the tricycle, and we were off. Ex pedaled like mad and I helped by leaning into the curves. It was so much fun. We both laughed and laughed.
                           
Even better, we won! True, the prize was an expired gift certificate to an ice cream shop, but it was so much fun. I did a lot of things with Ex that I never would have done without him. I'm still doing things I wouldn't have done before. After all, magic happens outside of your comfort zone.

Where did the fun guy disappear to the second we got married?