Hi Jessalyn,
The sentiment that his feelings haven’t changed in 4 months of dating and the consequent desire to break up due to this doesn’t constitute a particularly worthy reason.
Your ex boyfriend is making it sound as though he is desperate to fall in love.
If he never truly showed you that he was the hopelessly romantic type during your relationship with him, there is a good chance that he was not being entirely honest when he told you that he is breaking up with you because his feelings haven’t changed.
There may be someone else that he has taken an interest in and now wants to pursue.
In other words, he may have just gotten bored with you and wants to try something new.
However, don’t be surprised if he suddenly starts trying to get your attention at some point in the foreseeable future.
Guys who leave a relationship for facetious reasons tend to come back when they realize that they are not getting emotionally fulfilled by whoever it is that they left their ex girlfriend for in the first place.