Mike...
As you can see from these replies, the answers are, "yes, people CAN find out your real life identity" and "yes, your activities in SL CAN come to light and affect your Real Life." These things that we've been discussing, though, are very much more the exception than the rule.
So don't let these cautions make you too paranoid or keep you from having fun. In the general course of things, unless there are some special circumstances (like a law enforcement agency getting your personal info from LL as part of an investigation), it takes a very determined and knowledgeable person to ferret out your RL identity. You are anonymous in SL, unless you choose not to be, or unless you are very careless.
If you engage in cyber-sex with an SL escort, (or do a whole lot of even kinkier things), there is, generally speaking, no legal liability. Again, with certain exceptions. However, you may find that there ARE moral effects. An SL relationship, or relationships, can affect your Real Life personal life. Time spent with an SL sweetheart is time away from your wife or RL sweetheart. We've had tons of discussions here about whether or not that counts as "cheating"...in either case, though, it can have a real effect on your Real Life. Some people have gotten divorced over a Second Life affair.
Bottom line: You can Do Stuff in Second Life and be pretty sure of getting away with it. It's presumed that you are an adult and can take responsibility for your own actions.