Have you thought about going dating casually?
My situation was different to yours, I started dating a client early last year, it never got really serious but we developed feelings for each other, December last year I find out he was seeing another girl and made her his girlfriend, they were together for 5 months and have now split up.
He then contacted me again last month by email to try and date again, he's emailed a few times since and states how he had missed me etc etc. I had very strong feelings for this guy he's 13 years older (I'm 23) than me and it's the first guy I've developed such feelings for, so it was really hard to find out he secretly had a girlfriend. We ended up stopping talking and I decided to go dating not looking for anything but just for the fun of it and it honestly helped me get over this guy. Now he is contacting me regretting his decisions of messing me about and I'm not interested whatsoever and I think going dating and chatting to different men who weren't clients (the only men I have sex with are clients at this moment) helped.
So I think dating casually simply chatting to men and going on dates may actually help you forget or atleast take your mind of this client. It helped me so I thought it may be a good suggestion!
Best wishes x