Wendy
What was the point of Wendy? If Paul never felt anything for her, why was he with her? Or was the point to emphasise his 'repressed' character and his inevitable loneliness?
shareI think it serves to show that Paul is still quite able to get into relationships, but his lack of passion prevents him from fully enjoying the companionship of a relationship.
shareI agree, to an extent. But would add that we see how Paul sells out a real life for therapy. He breaks up with Wendy for Adele, he sends leaves Max cooking alone to spend time with a dropin (at night) Jesse - and ultimately sends Max away (I think on some level for "Jesse" essentially... as he values therapy over life).
I don't know that Paul is without passion. I think it's just that therapy is his only passion. He tries to fill all of his interpersonal needs with the job.
Then he finds out in the end that he's gotten the short end of the stick - and probably isn't even as good at it as he thought he was when he sees Adele manage his advances - and that after finding he was deceived by his clients and left to wonder why.