Both roommates Leonard Hofstadter and Jim Parsons have their own quirks and personalities that fans of "The Big Bang Theory" have come to love, but each one of them has his own story arc to pursue.

During the ninth season of the show, Leonard embarked on a marriage with his long-time girlfriend Penny, while Sheldon deals with heartbreak, since his fellow scientist Amy Farrah Fowler just broke up with him. At the same time, both scientists are pursuing their own breakthrough theory.

Now during an interview with Variety, Johnny Galecki, the actor who portrays Leonard revealed why he specifically requested from producers the role of Leonard over Sheldon.

"It was a very selfish request on my part. I hadn't been able to traverse those stories of the heart. I've often been cast as the best friend or the gay assistant of whatever character got to explore those relationships," he shared. "I said I'd rather play this guy, who seems to have a future of romantic triumphs and difficulties."

Galecki wasn't wrong about his assessment of Leonard. He did encounter several difficulties, as far as the romantic pursuits of his character is concerned. However, after pining for Penny season after season and proposing to her countless time, he finally got what he wanted - and it was even Penny who proposed to him in the end!

Season 7 of the show dragged on their engagement, but after talking to Sheldon about it during the season finale, Leonard and Penny realized that it's about time they tie the knot.

This development is something that really thrills Galecki. "I'm excited that Leonard and Penny have finally stopped talking about it and have taken the plunge, but that doesn't solve any problems or answer any questions. So they'll have a new world of loving struggle," he said.

One of the struggles they faced is Leonard moving out of Sheldon's apartment. Sheldon resisted the idea, and in the end, they struck up a compromise - Leonard and Penny will live in her apartment on some days, and they will live with Sheldon on other days. Because he is terrified of fireworks, they agreed that every Fourth of July will be spent at Sheldon's place.

The two are also babying Sheldon now because of his broken heart, and it is especially difficult for Sheldon now since Amy has started dating other guys. She did, however, refuse to date Sheldon's colleague Barry Kripke.