And yet another; I've fallen for my SP thread... There are numerous threads on this subject, and literally thousands of posts.
Here's my take on it... Dating an SP will never work.
Recreational sex (ie "sport fucking") is different than emotional sex.
Recreational sex is what this "Hobby" is all about and that is what "your friend" is having with his SP.
Emotional sex is what a relationship is all about. The two cannot coexist... because one will be the demise of the other. I know that is not going to be a popular opinion on this forum, but it is almost always the case.
Us guys "hobby" because there is something missing in our lives: gratifying sex! Those of you with SO's and who are still in love with those SO's, aren't getting what they want, so they turn to SP's. That is what I call recreational sex. Once the SO finds out about it, the relationship almost always inevitably ends... because the spouse is unable to separate the two types of sex.
SP's hobby because there is something missing in THEIR lives. The financial means to live the sort of lifestyle they want. That is not to say that some (many) also enjoy their jobs, because many of them do. Sex FEELS good! (If done properly of course... as with all things there are exceptions to every rule...) I know many SP's say they do this for a living because they just enjoy sex so much, and while I'm not disputing that they DO in fact enjoy it, (I know first hand that many of them do...) they don't do it for THAT reason exclusively, because then they'd be doing it for free. LoL
Occasionally, there comes a time when recreational sex turns into emotional sex (for one or both partners...). If this feeling is mutual, (which by the way almost never happens...), that is when you consider dating an SP. However, unless the SP is willing to quit the business and find a new vocation and/ or means of living their lives to the standard they want, (e.g. Sugar daddy...) and the hobbyist is going to stop seeing other SP's, then this relationship is pretty much doomed. Its the nature of the beast. That inevitability is almost always 100% guaranteed.
Time and time again have I read and heard stories of SP's and clients trying to make a go of it, but unless they are both completely committed to the relationship and cut themselves off completely from other recreational sex partners, it won't last... It may survive for awhile because everyone is having fun, but eventually the inevitable will happen. In this case, the only possible solution is to have recreational AND emotional sex with the same partner... exclusively.
Having said all that, tell "your friend" to avoid all this drama, and see another SP right away.