I was advised to wait for 12 weeks to allow all the internal repair work to heal properly, and also to consider using a saddle that minimises pressure on the perineum (ie a cut-away style). I started back on indoor cycling on my Tacx trainer at about 12 weeks without any issues apart from having lost a load of fitness. Advantage of the indoor approach is you can control the difficulty, and can stop when you feel like you've had enough.
Good luck!