Brad Pitt recently put his fans in a tizzy while hinting at the possibility of an impending marriage to Angelina Jolie. He said, “The kids ask about marriage. It’s meaning more and more to them. So it’s something we’ve got to look at.”

Brad and Angelina have been in a relationship since 2005, after they starred together in Mr. and Mrs. Smith. They raise 6 children together and despite busy shooting schedules that take them across the globe, making them ‘hands-on’ parents.

In spite of work commitments and kids taking up most of their time, they make sure the spark in their relationship is kept alive by spending time alone with each other. Yet, they seemed to be content staying as partners, without giving their relationship a legal binding.

Pitt was married earlier to Jennifer Aniston and Jolie has been married twice before – to Johnny Lee Miller and Billy Bob Thornton. Why do these Hollywood couples who stay true to each other, raise kids together, and seem to be so in love, shy away from tying the knot?

Johnny Depp and partner Vanessa Paradis have been together since 1998 and have 2 children – 11-year-old Lily-Rose Melody and 9-year-old John ‘Jack’ Christopher. Even though Depp openly credits Paradis with having helped him become a better man, there is no talk of marriage.

Depp has earlier been in relationships with Kate Moss and Winona Ryder. Ryan O’Neal, best remembered for his portrayal of Oliver Barrett from the classic hit Love Story had a long-term live-in relationship with Farrah Fawcett. O’Neal and Fawcett were considered to be the golden couple of the 1970s.

Despite having a son, Redmond, they did not marry which was not a common thing back in those days. They met in 1979 and were together until Farrah’s death in 2009, after a prolonged fight with anal cancer. O’Neal hasn’t stopped grieving for his partner, “I hear her voice, I see her silhouette,” he said once. They were a team for close to 30 years, yet never took the matrimonial plunge.

Susan Sarandon met Tim Robbins, 12 years her junior, while filming Bull Durham. They were in a much-envied long-term relationship from 1986 to 2009. But they never married. They have 2 sons – Jack Henry and Miles Guthrie.

Susan was previously married to Chris Sarandon whom she divorced in 1979. At the time she stated, “I no longer believe in marriage.” When asked why she never ended up marrying Tim, Susan has said, I've always liked the idea of choosing to be with somebody. I thought that if you didn't get married you wouldn't take each other for granted as easily.”

After their breakup, Susan had people coming up to her on the streets, telling her how they cried on hearing of their split, because despite not having legal sanction theirs was considered to be a rock-solid partnership.

What makes relationships succeed? Does marriage kill the chemistry? Does making a union legal, rob it of its intensity and sheen? Does love last longer if there are no strings attached?

Let’s hope Brad and Angelina, the poster couple for living-in, give us some answers soon.