(askmen.com) - Sienna Miller's new love Rhys Ifans has asked her to marry him five times. Sienna - who has constantly denied she is dating Rhys, despite the pair frequently being pictured together - isn't taking their romance seriously, while the 'Notting Hill' actor is "besotted" with her and desperate for them to wed. A source said: "Their romance has been a big secret for months now. Friends believe Sienna sees the relationship as a bit of fun, while Rhys has fallen in love. Rhys wants the world to know but Sienna was keen to play it down - even though she usually flaunts herromances. "He is besotted, totally in love. He can't believe his luck. He has already asked Sienna to marry him about five times but Sienna just laughs it off. "His friends are worried that she will break his heart when someone better comes along." Rhys, 39, has reportedly fallen out with his two best friends, fellow Welsh actors Ioan Gruffudd and Matthew Rhys, after they accused him of "stealing" Sienna from Matthew. Sienna, 25, briefly dated Matthew in the summer after they met while filming 'The Edge of Love', and Rhys has been ostracised by his friends since he started romancing her. The source added to Britain's Daily Mirror newspaper: "Rhys Ifans' name is mud among his former band of Welsh acting buddies. They all think it is disgraceful behaviour that he stole someone else's girl." Sienna's close friends are certain the relationship will not last because Rhys parties too much and lives "like a student". One friend said: "He blows everything he earns on going out and drinking. He lives like a total student. His place is a mess. He has lots of really weird habits."