I have been dating an older man for 3 months. We are both in school and our schedules are busy. It is now summer and schedules are not as hectic. He mentioned through texting we are exclusive. Everything has been great and we have amazing chemistry. But he does not reply to my texts... and he finally told me that I am too much of a distraction and that is the reason he does not text back. I will text him everyday but he texts a week later. He told me in the beginning he could not have a girlfriend but I did not ask him why since it was our second encounter. I also have not seen him in three weeks and it is almost going to be a month. I am getting very impatient and I am not a patient person. I know he likes me very much and I do too. We have told each other this. But I really do not know what to do and I am very confused. Why did he say he can't have a girlfriend meanwhile he has several throughout his life and why am I such a distraction he can't reply to my text? He has told me he needs to straighten his thoughts out. Is he playing me or what?

Ask him ''How am I helping straighten your thoughts out when you can't even talk to me because I am such a distraction?''
A, Either he is sincere in wanting a future with you but his priorities have you put you on the back burner.
B. He may not be sure what he wants but doesn't want to lose you until he figures it out so he put you on the shelf.
C. He doesn't want to see you interested in someone else because he has some jealousy thing thinking of you seeing someone else
... None of these are fair to you so unless he starts communicating and having more of a relationship with you you can only assume the negatives

How much older, 10 years, 20 years, 30 years ?

You do not have to be exclusive, if you do not want to be, how often to you actually date, see each other.
Texting once a week is not a boyfriend normally.

This guy is not into you. If a man does not contact you in three weeks or more, he is not into you. He has told you that you are a distraction. You need to listen to him and pay attention to what he is doing, which is nothing. Stop waiting on this guy. Don't let him keep you on a string to pick up when he feels like it.
It's only been 3 months, you are not that important to him, time to walk away.
He could be married. How old is he?

Its been 3 months and already you are seeing that a relationship is not his priority. Don't ignore it and wonder what he means as he has shown you with words and actions.

You tell him that you are no longer exclusive, and look to better options, and opportunities for romance. Ignore the red flags of warning at your own emotional peril.