I am not really sure. Based on the Sun signs, both being Earth, you should both be down to earth, and sort of reliable and trusting with each other. I was married to a Taurus and he was a bit possessive but in a romantic way. It's not really a jealous sign, it's ruled by Venus. Taurus men do like women but are generally faithful. There has to be more in his Natal Birth Chart, and something other than his Sun sign is causing this behavior. People often have planets in the sign next to their Sun sign. If he has planets in Aries, that would make him insecure and worried he may lose you.
Why have you been dating for 9 years? That's a long time to make up your mind about someone. I understand it may be hard to leave, but if you have trust issues and haven't resolved them in all this time, they aren't going to change. Maybe it's time to move on?