I once started dating an SP outside the business. We even had boyfriend/girlfriend sex no charge. But, it didn't last any more than a couple of months. She was too f'***d up to be able to carry on a serious relationship. She made it clear to me on our third session that she was into me and wanted to get to know me outside the agency. I also had a relationship with an SP that was not outside the business but she would stay with me for 2 1/2 to 3 hr. and charge me for 1 hr. Once she saw me for an hour, went to another call, and came back to my hotel room and spent the night with me. But, the day came when I phoned for her and was told she was no longer available. She had given me her personal number but when I phoned it a guy answered and I hung up.
I also had a two year relationship with a Russian dancer. The second time she danced for me we spent the night together. No, she did not charge me. That started a long term relationship that ended up breaking my heart when she moved in with some rich guy, which I was not.
So, yeah, I guess it happens, but these stories seldom have happy endings.