I understand your worries. As you say you have just met him. You can’t tell him all your past story of course, but maybe, if you can tell him that you have an insecure personality, the guy will understand you a little better and be prepared for the difficulties.
And please, don’t think any relationship is perfect, either. Any relationship have difficulties because there are two parties. You don’t have anything wrong and you are working on your issues as I can deduce from your post.
I understand that you are very scared. There are marvellous people who are gonna be ok with you and accept you as you are, with your insecurities but also with your virtues. And this guy can be one of these persons.
Keep fighting and have hope.
Don’t stop working on yourself because it’s not only gonna be good for you but for this guy or other possible future ones.

Congratulations. Enjoy this relation.