I agree with everything that Kin said, people who claim to love us will sometimes take advantage of us, because they know that it will be hard for us to refuse them or turn against their using us. Your original question was 'why do some guys use women in relationships', and the simple answer to that question is, 'because we let them'.
If we spoke out about what a man does, or if we showed him that we would not accept it and that if they are not willing to stop or change, that we would leave, then they might act differently. Have you ever heard the expression "you teach people how to treat you"? We do, we teach them, every time they do something we like and we respond positively, and when they do something we don't like, we react negatively. So it's important to speak up about how you feel or else you cannot say that they knew what your feelings were.
I too suggest that you talk to him about how much you make. Although you have been doing this for a long time, and it may be scary to step outside of this comfort zone, you have to put yourself in a position to want to do more, and to want to be more, and if he's not willing to support you in this, then you may have to think about leaving him...whether you leave the job, or the relationship is totally up to you and what you expect out of both.
I welcome your thoughts, let me know if you want to talk more.