BF Distant After Serious Talk

So my BF and I have been together for a little less than 5 years. He brought up marriage a few months ago and I suggested that we should get premarital counseling before getting engaged...and he was pretty upset about my suggestion. I compromised and found some premarital questions for discussion and he agreed. However, every time we attempt to start the the discussion he would always appeared to be upset/annoyed/impatient with my answer if they aren't exactly the same as his. A few days ago he asked to discuss premarital questions again and yup he looked upset again after my answer. I told him that if every time we try to talk about marriage we end up arguing what does that say about our future? Ever since then he has become distant. Has this happened to anyone? To me it's a warning sign if attempts in talking about the future results in arguments perhaps he has realized the same?