Long question for people in first love relationship or can offer opinion/ answers on one

BACKGROUND:

So we started dating in 8th grade and we dated for a little over a year, he had some severe depression and trauma he was getting help with my I couldn't handle it and my mom recommended we broke up so we did during the first semester of freshman year. Two years past and he dated other girls and even a few guys, I flirted with people but never found anyone I actually wanted to date as most just wanted sex. We got back together in 2018 and have been dating since. He has gotten much better with his mental health and is a very empathetic guy that makes me happy we don't even argue (though we do sometimes disagree and have passionate conversations but never screaming or anything like that). We started college about 3 hours apart and he regularly would ride a bus for hours just to come see me on the weekends. During covid we went months without each other only talking over social media because the health risk prob 6 months without each other. Now we are seeing each other in person on weekends when we aren't working and I love him of course but we had a conversation I'll mention below in a sec. So incase it matters our sex is great I don't always finish and neither does he but we both enjoy it and are Very open with each other and have great time (he a few years ago told me I was better than anyone he has ever been with)

THE QUESTION:

Well we are 21 now and we had a conversation where he outright said he loved me and wants to marry but he understands that I've neve had the experiences he has had. And that he was willing if I ever wanted to try letting me date other people (he mentioned girls and then said guys too but he is still working on the confidence for that to be 100% okay with him) and I've of course wondered about dating other people and why I might have missed out on. And I'm just wondering if anyone else has ever been in similar boats cause of course I love him and he brought it up but I honestly don't think he is actually okay with it more just is willing to do that so I can be sure. But anyone the question is what am I missing out on or is first love possible? I'm not really sure what my question is but I want to speak to someone else in a similar situation.

Thanks also I'm new on app (was looking for a couples app so I could ask but this came up and the tracker is kinda nice) so sorry if I used the topic stuff wrong😅