I guess I'm in the minority here. While I agree that it's a red flag worth noting and it warrants you keeping an eye on things, I also find that as we all get older, and we have more and more baggage that we carry around with us, all of us have random, knee-jerk reactions to things that trigger us for one reason or another and that we wish we could do over.
It would have upset me, too, to be on the receiving end of a reaction like that. I'm glad you called him out on the fact that he was projecting his stuff onto you, and basically telling you how you should feel. But I also agree that it's the actions that are the most important thing. And his ACTIONS show a commitment to you and your relationship. Who knows what things in his past may have prompted his reaction? Perhaps his rebound relationship involved early declarations of deep love and planning for a future. Or perhaps the partner in that relationship assumed those things were coming, and he has guilty, or fear, surrounding that. The possibilities are literally endless. I'm not advocating giving your guy a free pass to act like a controlling jerk. I'm simply saying that if this incident was an anomaly, don't forget to remember the good stuff, too.