Maybe, but most likely not. It sounds like this was a first-love situation, so it's likely that you are both very young. First loves tend to be very emotional, and the most intense. Most young people don't know what they want yet. They are flakey and make very bad decisions. Young people often aren't mature enough to make major life decisions like getting married. If he got married and divorced all within a period of the past 2 to 5 years, then this must be another one of those flakey bad decisions.
So it's possible that you caused this emotional change, but it's also possible he could have become like this with you, even if you didn't break up with him. He may have started doing all of these things even to you, when he got bored of you.