Dear sample27:
As far as I know, Seroquel is used basically to sleep and as another effect, will reduce your manic cycles and sex desire and yes it is a possible medication for bipolar treatment (my bipolar wife and many other BPs I know are taking it).
What I also know is that during manic cycles, flirtration, provocative dressing, irresponsible or unsafe sex and promiscuity increases significantly.
Do not confuse, however, manic BP cycles with addiction to porn. When you start going to porn sites is like when you start smoking or taking drugs or alcohol: it becomes harder and harder to stop.
I think it's better to see a psychitrist with good reputation for bipolar cases and try to sort out what you have and medicate. Seroquel is used as one of the medications for BP, but never alone as far as my 28 year experience with my wife goes.
I hope this helps. I keep you in my prayers,
LongTimeSufferer