<human>: Can you condense the text into a few key points?

Hi, 

I [23F] have been dating my boyfriend [22M] for almost two years. We have a great, healthy relationship.

However, a few days ago, he confessed to me that he has been having doubts about the relationship. He knows that cares about me very much, he knows that we have a great relationship that both his and my friends are envious of. The issue is that this is my boyfriend's first and only relationship. He said that he wonders what it would be like in other relationships, he said that he sometimes misses the freedom and lack of responsibility of singledom, and he said that he doesn't feel like it's fair for me to be in this relationship when he is experiencing these doubts. 

I understand his feelings and doubts, but I've been in several other relationships and I believe that what my boyfriend and I have is special and something that I want to sustain. I feel like if we had started dating after my boyfriend had been in other relationships, then we wouldn't have come across this issue. I don't know what to do, and I don't know what to tell him. 

Has anybody else been in this situation, and if so, do you have any advice for me?
<bot>: This is my boyfriend's first relationship, and he is having doubts about committing to this relationship. What should we do?