It's a great sign - he wants his friends to meet you.
I don't see why you shouldn't be cautious. If you've been hurt before it's only natural to be defensive. But you could explain to him that you're feeling worried but that it isn't his fault. Then if you say or do anything arising from that he will understand where it came from.
Take things slowly and let them develop naturally. I'm sure he will eventually do things that you don't like - no one's perfect. But as long as it's something you can handle, and you know he is basically a good person who makes the effort you'll be fine and your heart will heal.