Recumbent Exercise Bicycle

I love using the stationary bike, EXCEPT that the seat on it really hurts to sit on after 15 or 20 minutes. I could pedal forever if I could just sit comfortably. For awhile I sat on different pillows, but then that eventually was more uncomfortable then sitting on the seat itself. Is there any way to change the seat of the bike, or put something over it thats more comfortable? Has anyone else with this problem been successful with something? Should I just get a recumbent bike? I don’t know how those compare to upright bikes. What should I do?