I need advice for insecurity issues..

Hello! I'm currently in a relationship with my long term boyfriend. We've been together on and off for about 4 years but we haven't broken up in over a year now. I've been insecure since a year into the relationship. He used to look at women (particularly white women), I've caught him checking out my friends butts, I've seen the girls he used to chat with to meet up and date 2 years into our relationship (one of the reasons why we broke up). Since we got back together the last time over a year ago, he's been VERY VERY GOOD. Whenever we are out in public, he makes sure his attention is all on me, either he hides\deletes his chats and I don't notice them, and he calls me on his way home from work.. But I still feel EXTREMELY insecure. I ask him so often if he'd love me more if I was white, I still get paranoid if he chats with other girls like he used to.. How can I feel reassured? I'm definitely not the jealous type.. I'm usually chill and always give the benefit of the doubt but this insecure feeling is killing me.. if you suggest I speak to him, what should I ask or say? UPDATE: He's not a very attractive guy. I feel like he settles for me because I got my shit together, I cook, clean, full time job, go to school, and I'm a decent looking girl. I fear that if a white girl gives him the time of day, he'd leave me.. I've been debating whether or not to stick with him because of this dreaded feeling.