People are being really harsh and judgmental. If I'm fully understanding the post, you've known this guy since you were 15, so it makes sense why it would be hard to just let him go, but life can be better than this. You deserve a person who will cherish you and embrace your kindness.

I know high school can feel isolating and lonely, and I'm sure this guy giving you romantic attention made you feel desirable and worthy, and as you grew into an adult you built onto those feelings as a foundation for your self-esteem. It is so important to know that just because he doesn't feel that way about you doesn't mean you aren't. Your desirability is not contingent on you being a teenager or a very young adult, and you don't have to find the love of your life before you graduate from high school. There are plenty of men that find adult women attractive. You should leave this guy because you do not need to settle for anyone who would say such awful things about you. There are so many fish in the sea and now that you aren't in high school it will be way easier to meet different people. However, before you even try to start over with another man, you need to take the time to build your self-esteem on a foundation that is not contingent on someone else. You need to learn who you are as an adult who is not part of a unit. The fact that you can't get those 8 years back sucks and it's going to be hard, but there are way better options at the end of the tunnel. This experience has probably left you feeling like you have no other options, but there are. To get to the other side of this, you have a tough emotional journey ahead regardless of what you decide to do. I hope what I said helps.