Only your surgeon can discontinue the use of your abduction brace. As you said, it is designed to help prevent a hip dislocation. After all you've been through, you don't want to end up with a hip dislocation and another operation.
When the hip is replaced, many of the muscles around the hip are cut. This leaves your joint unstable and at risk for dislocation until everything heals.
Some doctors advise using an abduction brace for daytime wear. Most require an abduction pillow for sleeping at night. Keeping this position prevents the hip from popping out of the socket.
However, some new research has called the use of abduction braces and pillows into question. It seems that patient function is less with these devices. They may not be needed as much as was once thought.
New, less invasive surgery with smaller incisions and less damage to the muscles may be helping. Depending on the type of surgery done, some surgeons are doing away with this device. Even so, it's best to check with your doctor before leaving the brace off.