I completely understand where you’re coming from. Though you guys may not have been 100% fully exclusive, the feelings of hurt would still be there. I feel if you’re spending that much time with a guy, he would have enough respect to focus on you and only you. I think if he’s proved he’s trust worthy over the last 2 years, you should push any ideas about breaking things off, a little to the side. If he’s been good and loyal to you when you’re 100% official, that’s what really matters!! I don’t believe you’re over reacting. Just have a solid conversation with him, and voice your concerns on this. And make sure you know you can trust him from here on out