Lindsay Lohan's Sugar Daddy -- We're NOT Dating!

Lindsay Lohan is ABSOLUTELY NOT in a committed relationship with the rich and famous artist who lets the actress drive his expensive cars whenever she wants ... this according to the artist.

In case you forgot, Lohan was driving Domingo Zapata's fancy Porsche in NYC last month when she allegedly struck a pedestrian in front of the Dream Hotel ... where she was later arrested for fleeing the scene of an accident.

Rumors immediately spread that Lindsay was dating Domingo -- but this week in L.A., Zapata made it clear, it just ain't true ... the two are "just friends."

But that doesn't mean Domingo ain't lookin' -- dude tells us he looooves the ladies.