Hi , welcome
Opposites attract. That's why you found each other and likely why he isnt going with one of his friends.
There is a fine line between being possessive, being protective and having unfair expectations. Being in love elevates these feelings with some people.
In your situation I'd slowly seek out his deep feelings for you then evaluate if he has commitment within, trust and you are satisfied with that. Then let him know that you feel a little jealous of other girls and need regular reassurance. There is nothing wrong with being very honest however be aware that his personality dictates his enjoyment of social contact so while it's ok the be protective of your bond you must allow him to be totally himself. That means not putting any pressure on him making him feel guilty.
Ensure your relationship is very special by getting to know him very well is essential as is a very close friendship.
Good luck
TonyWK
