How to make boyfriend feel less insecure. PLEASE HELP!

So in highschool I had this amazing boyfriend for 3 years. We never really broke up but we are attending colleges in different states and we agreed that we didn't want to try to keep a long-distance relationship especially since the only dating experience we have is with each other. We decided that if it was meant to be we would end up together. However, its been really hard for me. We've agreed to keep contact down to a once-a-week text conversation to make things "easier". However, I'm dying to hear his voice and all I do mostly is cry over the Instagram pics of him and his new girlfriend.

Anyway, things have gotten better and I'm starting to see this guy in my math class. He's super cute, quirky, funny, etc but he's never had a serious relationship. I can tell he's intimidated by the fact I've had a relationship for over 3 years. I'm not sure if he's fully aware I'm still in contact with my ex..... But he does know I lost my virginity to him. The guy I'm currently seeing wants to hold out until marriage, which I'm totally cool with. I told him I don't expect sex from our relationship but I feel like he doesn't believe me/ is jealous I've had sex with someone else. I just don't know what to say to my new boyfriend. Like how do I make him feel less intimidated by my previous relationship? I'm honestly ready to move on. I feel like I need more experience and I really want this new relationship to work out. Thanks to anyone who read this all. Any advice will be appreciated!!! :)