The Little Fockers actress, who gave birth to her second child on Saturday, explained that she felt instantly comfortable around the actor when they met.
Asked whether she is open to the idea of reincarnation, Alba replied to Style: "I'm not closed to that possibility. I definitely felt like I knew my husband when I met him. It was an instant comfort when I met him. I felt like we were family."
While the couple didn't plan to have their 3-year-old daughter Honor Marie, the 30-year-old star explained that it has brought them even closer.
"It just happened and we were like, 'OK, let's do this'. It's made our bond deeper. It's creating a life that you created with someone else that makes everything more solid," she said.
Alba also insisted that she is in no rush to return to her pre-baby body because she is at ease with the way she looks.
"I'm much happier with my body than I've ever been," she explained. "It's different, but it's fine. I had a different association with my body and what perfection was when I was younger."
Alba will next be seen in Spy Kids 4: All the Time in the World, which comes out in US and UK cinemas on August 19.
Watch the trailer for Spy Kids 4: All the Time in the World below: