The other three girlfriends are met online from the dating websites, as
Aside from the amusing interactions between Niko Bellic and the women he dates, there can be several in-game benefits to starting a relationship with any of the datable characters.
The ability to date girlfriends, first introduced in Grand Theft Auto: San Andreas, returns in Grand Theft Auto IV.
Don't take your friend to an activity that he doesn't like or your 'like stat' will reduce.
You can perform upto four activities on each outing in order to give your 'like stat' the highest possible boost.
But I'd personally rather them to have focused on developing something else other than that. You HAD to go on those stupid dates for the story (as well as for achievements).
The relationship aspect of Grand Theft Auto IV is perhaps one of the most nebulous areas of this epic game.
Each friend offers a 'special ability' in return for maintaining a good friendship.
In order to unlock a friend's special ability, you must have a high 'like stat' for that friend, and this stat is based on how regularly you hang out with your friend.
Each woman has different tastes and will respond accordingly.
Reaching 100% fondness with all five girlfriends is not required to achieve 100% completion of the game.
However, that shouldn't daunt you from building as many relationships as you can, because they happen to provide some of the deeper and more rewarding experiences Grand Theft Auto IV has to offer.
In fact, without building up relationships with myriad characters in the game, you're going to miss out on a lot of what the game intends for you to see.
Most likely not, if you can go do a "quickie" with any girl in the club, I don't think being tied down in a partnership is high on Luis's things to do, but we wont know till the game comes, 3 Days, 22 Hours. From the looks of it it seems luis will be able to dance to impress the ladys, and his reward will be makeout session or bathroom humping.