Put it this way...in films where his love interest doesn't have a significant role or is one of many like ensemble casts its usually a black woman..
Films where Will Smiths Character SO has minor role in the story:
ID4 - viv foxx - big ensemble cast - black woman
Enemy Of The State - wife is minor role - regina king - black woman
Ali - bio pic - it is what is - black women
Pursuit of Happyness - wife has minor role - Thandie Newton - black woman
I Am Legend - wife has minor role - Salli Richardson - black woman
Seven Pounds - wife has minor role - Robinne Lee - black woman
Films where Will Smiths character SO has major role in story:
Wild Wild West - love interest has major role - Salma Hayek - latina
MIB 2 - love interest has major role - Rosario Dawson - latina
Hitch - love interest has major role - Eva Mendes - latina
I Am Legend - possible love interest and ONLY SURVIVING ADULT FEMALE in the film - Alice Braga - latina
Seven Pounds - love interest has major role - Rosario Dawson - latina
Films where Will Smiths character has significant contact with a white women:
I, Robot - white woman with major role - Bridget Moynahan - platonic
Hancock - white woman with major role - Charlize Theron - may as well be platonic
Bad Boys - white woman with major role - Tea Leoni - never realized on screen
Men In Black - white woman with major role - Linda Fiorentino - professional relationship
The ONLY film where his love interest play a major role AND was black was Bad Boys 2..out of all those movies