With baby number three on the way, Mark Wahlberg is committed to making his family life as successful as his film career – and that includes marrying longtime girlfriend Rhea Durham.

"We continue to grow in our relationship," Wahlberg told PEOPLE on Thursday at San Diego's Comic-Con International, where he was promoting his upcoming film Max Payne. "I think we have a much better chance at succeeding and staying together."

The 37-year-old actor and longtime girlfriend Durham, 30, plan to have a formal wedding next summer after their baby is born.

"I wasn't prepared to be married – I don't care who it was – at [age] 20 or 30," said Wahlberg. But now, he says, he's ready for "committing to really making it work constantly and all the other things that go into building a solid foundation."


Gives Up the Fast Lane
Wahlberg said giving up his fast lane life style – the kind of late-night action that inspired Entourage, which he produces – has been crucial to finding his way as a husband and father.

"Before I couldn't manage to go to school for four or five hours a day and then be able to get my homework done," he laughed. "But once I took out the nightlife part of my life, you know going out from 10 to 3, 4, 5, 6 in the morning, there's enough time in the day to do all the stuff I'm doing and then some and get a good eight hours sleep."

Now his entourage is primarily Durham and kids Ella, 4, and Mike, 2. "My family travels with me when I work most of the time, or I go back and forth on weekends," he said. After a busy slate of film projects, he now has "a good four or five months off. I try to take as much time off as possible ... Mommy's had enough of Daddy being away at work."

Not all the guy-play is gone – at Comic-Con Wahlberg was working his cell phone to coordinate a tee time at Torrey Pines golf course with his pals. But the Max Payne video game on which he movie is based was off limits.

"I didn't want to play because I have an addictive personality," he says. "I got more responsibility now than I've ever had with the kids and everything else. I don't want to be spending 14 hours on the videogame and then eight hours on the set. It's not going to work out."