Im afraid my boyfriend will never care about as much as his ex?

Im seventeen and ive been dating this guy for three months. He dated his ex for three months. Weve always like each other just never acted on it. His last girlfriend was special to him cause she was his first ual experience. When she broke up with him he was really hurt like he told people that she was his best girlfriend and he didnt love her for how pefect she was but he loved her for how imperfect she was. Should i question him about his feelings for me and his ex or would it make him uncomfortable. Also i have a cousin who is his best friend and they almost hooked up at one point. He always flirts with her and puts his arms around her. I feel as if i would never be as special to him as she is, cause he once told her that shes the one girl he could see himself marrying later in life. How would i talk to him about this or should i just forget about it and see wat happens?