Am I just jealous?

Just tell him that it bothers you when he leaves you to go see other girls. If he wants to be with you, there are certain things that shouldn't come before you. You need to let him know that you love him and tell him how you feel and thats why it bothers you when he leaves like that. If he only gets dressed up for special occasions that would kind of worry me. But you have to trust him. Don't go through his things, its his own privacy. If he feels the same way you do to him, he should tell you everything. Good luck hun.