If it's not his choice, one of two things may happen.
Just because a guy is pulling away, doesn't mean he's losing interest in you altogether or that you have anything to worry about.If he's taking a step back and claiming some space for himself, it doesn't mean he doesn't want to be vulnerable with you.It just means he wants to prepare himself and make sure he's ready for it. Don't try to force him to open up to you, and don't put pressure on him. Demonstrate that you can be patient and low-key, and that you aren't going to push him to be vulnerable with you before he's ready.He may take a step back, but he knows if he disappears, he'll be risking the relationship. He still wants to see you – If he's distancing himself, he'll still be open to seeing you, just maybe not as often.He becomes erratic or unreachable – If the man you're seeing is really losing interest, he'll give one-word answers or stop responding altogether. It will be clear – It will be painfully clear that he's on his way out of the relationship.