boyfriend insecure about my sexual experience

Hey guys,

In need of some relationship advice. I just had a very emotionally draining conversation with my boyfriend of about a year. I love him so much, and I know he feels the same about me. He was a virgin when we met, and he really hadn't had much dating experience, let alone sexual experience. In fact, I was his first real kiss. He's 20 and I'm 22.We moved very fast in the relationship, we had sex on the first date and we became exclusive about two weeks after. But...it worked for us. We're madly in love and very, very happy.

However, some insecurities have been popping up on his end, and it's in turn making me feel crappy. He knows that I've had my fair share of sexual experiences before meeting him.

He has brought up the idea of a threesome on multiple occasions. I always joked with him about it and dismissed it as typical guy behavior. But then, after probing a little further into the fascination, I've come to realize that it's actually a way of manifesting his desire to become experienced with another woman besides me. When I asked him about it, he said that was true. He said that he feels like he's sort of less manly because he's only been with me. He said I'm the only one he sees himself being with, and he's kind of insecure about the fact that I've been with other people and he hasn't.

I tried to soothe his worries, and after being unsuccessful with that route I, being not so serious, yet curious about his response, suggested he just go out and do it then. He then retreated and stated that he knows that would make me feel bad and would never do that to me. He said he was sorry for bringing it up and was just going to "push it out of his mind." When I asked how he could do such a thing, he replied with "because I love you that much."

Long story short, his insecurities are making me feel insecure. If he's so fascinated with getting experience elsewhere, and just "pushes it out of his mind," even when it's so clear that it bothers him, I'm worried it's going to manifest again in the future...and possibly lead to some infidelity. It's not that I don't trust him. I do. I'm just a very anxious person with some insecurities myself.

Any takes on my situation? Any advice?