Dawn, It sounds like some of your husbands faults are down to you. You have allowed him to be this way - probably since the beginning. I'm constantly surprised by women who acquiesce to their men, because they lack confidence and courage to demand more from them. Did or do you suffer from low self esteem per chance?
I think you need to take a good hard look at yourself and ask yourself why this "good man" doesn't show enough interest in you or the things that interest you? Why is he so self centered and selfish? Basically because you've let him be this way from the outset. Ever heard of 'start as you mean to go on'?
It's time you started making your presence felt. It's time you turned HIS life upside down. Don't just walk out without giving your husband an opportunity to shape up. You soooooooooooo need to make a stand - not a half assed one either. You work out what it is you want from this guy and you demand it.
If it doesn't work out then leave. I can see why you would want to leave, but I wouldn't be so fast to give up on your husband. I'd be letting him know, in very clear terms, just how fed up and desperate you are and that if he doesn't lift his game you are gone. But make sure you know what it is you want from him.
all the best
Marilyn