Sad decision by one of Hollywood’s most delightful female stars, CHRISTINA APPLEGATE, who’s telling pals she’s definitely off the marriage market after her devastating double mastectomy – and the shocking drug overdose death of boyfriend/photographer LEE GRIVAS.

“Christina’s just not up for a second marriage, or even a serious relationship,” said a close friend – although she’s not ruling out casual dating and refused chemotherapy so that having children would still be possible.

Insiders reveal the star longs for a drama-free life and will devote herself to her breast cancer awareness foundation, Right Action for Women.

“Christina’s always been involved in women’s cancer issues, given her mother’s history with the disease – but after her own breast cancer battle, her driving force is to help others,” said a friend.

“And even though Christina says she’s doing great, it’s only human nature to wonder, after an ordeal like hers…Is the battle really over? She knows it may not be, but she’s getting on with her life.”

(Let’s wish “Good Luck” to a great lady!)