Advice on setting time boundaries with clients?

I’m not a confrontational person and this is an otherwise awesome and regular client. This client always wants to be my last appointment of the day. My schedule isn’t full so I absolutely can accommodate this. I have also given extra time up to 10 minutes at end of appt, again due to me being new and wanting to make good impressions with clients. The first time I did this, he was very thankful which then I made the mistake of replying “of course, I don’t mind as it’s my last appointment. After this, the client immedietly took it as a reason to request last appointment slot Every time. This has led to him being late for appointments and making appointments run way later. I’ve tried to say the last spot is taken, but he will then request to book in advance to ensure being my last client of the day. I find myself going home almost an hour late. He has shown up 30-60 mins late on 3 occasions. And is consistently Atleast 5-15 minutes late always. And even when on time, I am going home atleast 30 mins late anyway. This is frustrating because now he knows he’s my last client and it would be obvious I’m upset or frustrated if I cut time from appointment, where as if I had another client after, I would have an excuse to cut off the time. He also expects me to pause time while switching body parts or getting up to stretch. This is because I normalized pausing time when I was newer. This is an awesome and dependable regular client otherwise, and it’s my own fault that all of this is happening. I also cant afford to piss off a regular client. What can I do to steer to slightly more boundaries during appointments? Thanks