Join a book group or other club in your area (even virtual). Go to church or other religious institution. Join some committees in your community (local government, etc.). That’s the best way.
Fluther doesn’t have many people and all are scattered all over the map.
If you have the cash, you could buy a Realdoll instead.
Would be about as real as any “girlfriend” on the internet, and probably cheaper in the long run.
Unless you are on a straight-up dating site, I doubt people would jump right into the “girlfriend” part. We don’t know who you are and we don’t have any emotional connection to you.