Fontana, 28, and the 39-year-old former football player and entrepreneur are considering tying the knot in Ethiopia, reported Contactmusic.
"Rohan told me we have to return to the roots so the marriage will last forever," Fontana said.
This will be the third wedding for the model, who has two children from her first two marriages. Rohan has two kids from his first marriage to Geraldine Khawly and five with singer Lauryn Hill.
Rohan, who runs the Marley Coffee company, met Fontana shortly after he separated from Hill last year following the revelation that she was expecting a child with another man.