My $0.02 worth - I've never worked with an agent and whenever I used to gig, I'd always make arrangements myself (or let my wife do it - don't mind paying her outrageous rates ). You seem to rely on an agent for at least some of your bookings. The question I'd ask myself is this: going forward, am I going to be able to continue booking directly, or find a different agent or avenue of booking. If the answer is yes, as it is for many others in this forum, then ditching this unscrupulous agent is the way to go. On the other hand, if I get this gig, booking directly, but this will dry up a major source or bookings, then it may be worth it to be accommodating with this guy.

Generally we turn to using an agent when we don't want to deal ourselves with the business end of the music business, and would rather pay someone to do it for us. From your other post, it sounds like you are doing allright dealing with the clients, so the only potential benefit your agent was bringing to you is making contacts with the prospectives.

I think these days with internet and loads of data at our fingertips, everyone can find a way to market themselves. So an agent is becoming a thing of the past. Even if you use the agent, I'd try to stay away from exclusive arrangements - if he brings you a gig, he gets a (reasonable) percentage, but if you book yourself, you owe him nothing. Around here, even the real estate agents can be engaged this way. This way you don't have to be loyal to someone who feels no loyalty to you.

Best of luck,
Alex