Why are guys are so fucking confusing?

Anonymous
So this guy and i have a complicated relationship. He is in a relationship but we have been seeing each other for a while now because he really pursued me and i thought the feelings shared were mutual
Recently, his contact with me has been very distant (impersonal text messages) but whenever i reach out to him we converse as per normal. He recently traveled abroad for 3wks and during that time we kept in touch. Since he has returned - 2wks now (because of his seeming lack of interest in me) I've kept my distance but he occasionally sends me messages.
What is the deal? I reason that if he is not interested anymore, why contact me?
If he is, why is he giving a cold shoulder?
HELP! i haven't the slightest idea what to do or make of this.
Updates
+1 y
I noticed that the responses received emphasize that he is in a relationship but notice the latter part of the question:
What is the deal? I reason that if he is not interested anymore, why contact me?
If he is, why is he giving a cold shoulder
Why are guys are so fucking confusing?
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