Samantha Ronson is desperate to marry Lindsay Lohan because she fears the actress will become bored with the couple’s sex life.

Pals tell Closer Magazine Sam is certain that the sooner she and Lindsay tie the knot the less likely the Mean Girls star will be to doubt her sexuality.

“Lindsay’s always been rampant and loves sex. Sam just doesn’t know whether she will be able to keep her satisfied. She’s hoping that getting married will really seal the deal.”

Samantha spends as much time as possible with Lindsay, and her clinginess is creating tension between herself and Lindsay’s friends.

The source added to Britain’s Closer magazine: “Sam wants to be with her 24/7 and is incredibly possessive – but Lindsay seems happy with the situation.”