I've recently become one of Missy's 80% (and I've told her so)! I'll bite on the OPs questions:
How many of my fellow pooners have a SO?
Me
Do you find it difficult to keep the time and money spent pursuing your hobby difficult?
Time, not too difficult. Money, a little.
Are you ever worried about picking up an STI from a service provider?
For sure. Both SO and I are DD free and have an active (if infrequent) unprotected sex life. So I like to be safe and play safely. Um, generally. I have been occasionally weak over the years, though, with the BBBJ instead of the smarter CBJ. And I do stress about it when I succumb to temptation. Have been lucky so far, no stories to share. The few times I have crossed my boundaries I tend to promise myself I won't ever do it again, make up lame excuses why my SO and I can't have sex, and wait until test results come back clear. Unless I know and trust the SP well enough to be able to discuss such things openly, like one should do in civilian life. But with someone new, SP or civilian, it's not worth the stress unless you don't love your SO, and if you don't you should end it.
I used to keep the ring on, but I read somewhere that bacteria tend to lodge under them even when you wash thoroughly, so usually I remove it before showering at the incall, as a courtesy to the woman I'm seeing.