Yes the two terms are used interchangeably quiet often but precisely co-culturing should be used when two different microbial species are grown together in a medium while the term co-cultivation associates with cultivation of two types of cells or tissues grown together in a medium.
Co- culturing is simply when two micro organisms of different species are grown simulteanously while co-cultivation involves checking results of two already grown kinds of cells after the incubation period
In coculture, your objective is to maintain the two organism simultaneously on the same medium while in co-cultivation you are exploiting the beneficiaries of one organism to have some add-in to the second only perpetuated organism, say, as we see in tri parental mating in microorganism OR Agrobacterium mediated plant transformation..