Kim
The game's first girlfriend opportunity comes about halfway through the Division 3 season with Kim. Over the course of the game Kim rewards sponsorships with equipment upgrades that increase as the game goes on.
Tara
In Division 2 there's the option to dump Kim and her equipment bonuses for Tara. Tara's primary benefit is a decrease in the cost of steroids.
Grace
The last girlfriend, Grace, comes along during the Division 1 season. Grace offers a decrease in the cost of upgrades, and upgrades the medical facility for the franchise. She also grants a 10-percent bonus to stamina before the Division 1 championship game that effects the entire team's statistics.
Achievements
There are two trophies in the game associated with girlfriends. The Faithful trophy is gained by staying with one girlfriend throughout the game. The Playa trophy is gained by romancing all three girls over the course of one campaign. Since each girl offers only one chance, players seeking the Playa trophy must fulfill each challenge.