Looking for title of 70's film theme song

Hi everyone,
Can anyone help me please... I am looking for the name of a film theme song.
Very early 70's.. It was originally a french movie, starring Alan Delon & Verna Licci
The song went something like this... Staayyy, never go away, because I love you so.. Stay never go away because I need you so...
I know it isn't much, I appreciate any help.
Thank you
Amber

The only movie I found that starred Alain Delon and Virna Lisi was the 1964 film, "La Tulipe noire" (The Black Tulip).