L'Wren Scott feared Mick Jagger 'wouldn't be with a woman over 50,' source says

Fashion designer L'Wren Scott, 49, apparently took her own life in her New York City apartment on Monday morning, amid news that her business was millions of dollars in debt and she was struggling to make things right for all involved.

However, an insider close to Scott tells FOX411 says she was also afraid her 13 year romance with Rolling Stones singer Mick Jagger would come to an end.

"L'Wren loved Mick so much, she could not have fathomed what it would be like to be without him," a source told FOX411. "Mick would always say he would never be with a woman over 50... That was something L'Wren really took to heart."

Scott was to turn 50 on April 28. When she first the Rolling Stones frontman, 21 years her senior, she was a successful Hollywood stylist and costume designer in her mid-30s, with hopes of building a family. But having already been through multiple marriages with a slew of kids of his own, Jagger apparently did not want to go through it again.

"L'Wren sacrificed her desire for kids because she loved Mick so much. She absolutely adored his kids and loved them all very much," noted the source. "But being around all his kids and grandkids all the time often made her feel beyond empty. It was excruciatingly painful for her. She had wanted a family of her own so badly."

More On This...

Before meeting a life partner in Scott, Jagger had a history of dating beautiful, young women, and has seven children with four high-profile ladies. Marsha Hunt, with whom he has a daughter, was in her mid-20s when they broke up. Bianca Jagger (one daughter) was 33 at the time of their divorce. Model Jerry Hall (four children) was 43 when the pair ended their marriage, and Luciana Morad was 30 when she gave birth to Jagger’s son in 1999.

On Tuesday, Jagger wrote on his Facebook page that he is "still struggling to understand how (his) lover and best friend could end her life like this" and that the couple had spent "many wonderful years together and had made a great life" for themselves.

Jagger's rep told FOX411 to “stop looking for gossip that has no relation to fact to drive your ratings" when asked for comment on this story.