Green, 36, and Grant, 30, first met in 2007 at the reopening of their favorite comic book store, Golden Apple Comics, where Green was on-hand to sign autographs and Grant was photographing the event.
"We met that night but didn't have the opportunity to connect," he tells PEOPLE. "Then we met each other a second time at Comic-Con. We both had so much in common and kept running in to each other throughout the week."
After a mutual friend passed Grant's phone number to Green, the two met up for, as Green puts it, "a play date."
"I came over his house and we went and got some In-N-Out," Grant recalls. "And we ordered the exact same thing the exact same way, which was a little strange. Then we go back to his house and he turned on his TV and on his DVR [was] show-by-show the exact same things that were in my DVR. I was like, 'You know what? This could be a beautiful friendship.' "
Things got more serious for Green when the two hit the road together on the two-week Robot Chicken Skate Party Bus Tour last year. "That's when I knew that there really couldn't be anybody else for me," Green says. Adds Grant, "I didn't realize how deep it would go until we really spent time together. It was sad that we got off the bus and had to go back to our everyday lives."
As Green tells it, a future together was always on his mind.
"For a few months before I proposed, I was actually working on the ring with a jeweler that I knew," he says. "Eventually it just came down to us being in a very special place and me having the ring."
Grant says she "had no idea" that Green was even thinking of marriage. "I'm a very rational person,” she says, "so in my head I was mathematically breaking it down, like … maybe after a period of time it will be okay to move in together and then we can think about getting married."
As it turns out, Green proposed and the pair planned their May 1 nuptials in less than four months.
"The most important thing was putting everybody in a place where they could understand [our love] and see it first-hand," Green says of their wedding planning.
One detail both focused on was catering party favors to the individual guest. "We both like toys, so the centerpiece for each of the tables were different collections of toys that were takeaways," Green says of various action figures – think G.I. Joe – that waited for guests.
"My mom got the Care Bears," Grant says, "because she used to call me Clare Bear, and another good friend of ours had a pony collection so we made sure she got the My Little Pony table."
Back to the Future
While newlywed life is sweet, there's no honeymoon plans yet for the two, who are busy with various projects.
"We got invited to participate in Paul Haggis's Artists For Peace and Justice," Green says, "which is doing a lot of on-the-ground work in Haiti. We've just started getting involved in it. "
"But Clare is an amazing partner," he continues, "an exceptional woman and such a great friend and person who sees things the way they are and really takes the initiative to make her life and the world better."
Adds Grant: "Everyday proves how amazing [Seth] is, [how] special he is and down to earth he is and I've never connected to anybody as perfectly as I do Seth. I just feel so lucky that we found each other."