Practical advice Perna. Let me add:

Make a list of some statements and memorize them.

"I wasn't doing anything wrong, or against you or our relationship. I remained true to you the whole time I was out. As for the details of "who" I talked to all day and "what" we talked about, you are just going to have to learn to trust me."

"I can't control how my family thinks, and neither can you. But I will remain true to you throughout. You are going to have to trust ME, even though you may be bothered by someone in my family."

"Your fear of what I am doing when I am out of your sight is driving me away from you. The very thing you fear is being created by you. Don't you see that?"

The main theme here is his lack of trust, and it's damaging effects. He will ALWAYS try to turn the conversation back into "justifying his anti-trust". That's a different track. Don't entertain that discussion/argument. (Do your very best to remain guiltless so that he can't throw anything in your face, to pull the argument back to his track)