Abused Dog - Rare breed - Behavior Problems

Question
We have a rare breed from Thailand, a Thai Bangkaew.  He was very abused before he was brought over to the US and has always had a problem with new people.  He has now accepted my husband but is very aggressive towards everyone else.  If you are not my husband he has a problem with you.  He is 5 years old and we've had him for 3 years now.  He has a VERY mean growl and a loud bark.  He scares anyone and everyone he comes across.  We are afraid he may bite someone at some point but it hasn't happened yet.  We are at our wits end with him and we don't know what to do next.  We can't have people come over (ESPECIALLY MEN!) and even having him boarded is a problem because he doesn't like people he doesn't know.  Please help us, we are feeling trapped and don't know what else to do????

Answer
First,if he isn't altered,getting him done may help reduce aggression

Second this is a VERY serious problem,and I think the best way(the only way)to deal with this is through a a trainer that deals with aggressive dogs and one that can come to your house and see what the problem is,and when you call them,explain the problems you are having with him