Received several threatening text messages today from someone claiming to represent several ladies. Demanding compensation and threatening exposure if I do not comply. They even sent text to my SO claiming to have information regarding my activities. Has anyone else been threatened recently?

I never give real-life information for screening.  I only use provider references of ladies I have seen.  Sorry for your troubles, and I know it's little consolation to know they were avoidable in the first place.

They committed a Federal crime by using the phone to do that.   Possibly state laws too.  

The general advice is ignore it. If they do contact your family, "deny, deny, deny."
Don't give them any money. They'll just come back for more.

Honestly, this is fucked up. Sorry this is happening to you.

It has happened to me actually a couple of times. The problem for them was that I don't put up with that kind of crap. I was initially caught off guard. But i've spent my whole career reading people quickly, disecting holes in stories in a hurry and uncovering bs, and/or scams so I had to put something into play pretty quick.
With that said.....When mine contacted me, I took a couple minutes and went into action. But, before I go into it....  
Did you contact a provider using your actual number?
Did you reach out to a new provider who maybe answered initially but immediately stopped responding or did not contact you back at all.
Did the texter actually text your SO ir did they just say they were going to.  
The the person sent you disturbing pics and, did they also call you.

it is pretty much the same scam that has been reported by several TER memebers in these forum. Not sure what the best search terms would be other than "extortion" but you can find posts about this type of event.

If this is a real, tangible extortion attempt by a provider.

Did they really text your SO? How would they get her info? Either they googled you and made some lucky guesses or they stole it from someone. (Maybe from phone while you were "busy" or in the bathroom?).  
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If they google your phone number, that might lead to an address. Then, "others with similar names at that address" then phone numbers and emails, and ... Don't you just love how Facebook and others want to CONNECT everyone to everyone whether they want to be connected or not?
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Normally, "ignore" seems like good advice if it's a scammer (no personal info; just general threats: "We know who you are. We know what you did." stuff).  In the case of REAL info, I lean towards inviting LE into the situation. But, I would start with a lawyer who can give you BETTER advice and maybe represent you to the correct LE (FBI? NSA? ... local police doesn't seem right, but a lawyer can figure that out based your actual story and facts).  
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I think that most LE would consider extortion a better crime to go after than misdemeanor philandering, especially if they have no proof other than an extortionists accusations and _no admission of guilt_ from the party being extorted, if you catch my drift.
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GOOD LUCK!

Gee, how did they get your SO's number? Do YOU use your real phone number for making extracurricular arrangements?  If not, then there's a chance it's someone you know.

How did they know your SO's number to text her?

Everyone should have a Text Now Phone Number and change it every 6 to 10 months.

So I'm a lawyer for 44 years, but have no experience in criminal cases or stuff like this. With that proviso, here are my thoughts:

it was to start law school at age 15.   Lol

Oh no, those 5 years of college in the early/mid 70s were the best of my life!

http://www.youtube.com/watch?v=aZ2cqfoumDc
"Christ. Seven years of college down the drain. Might as well join the fucking Peace Corps."

This exact scenario happened to me this week. Started with a pict of my number on a people search site and threatened to out me to my SO if I didn’t make payment. All that scrapped info is so unreliable anyway. Pretty hard to trust any provider or site these days.

I’m a very trustworthy person, so we can agree to disagree. Not all providers are unscrupulous. Let’s just be honest we are all, so very different. Some people still have integrity. Pick a provider who fits your needs.

about 5 years a girl i had seen a bunch of times in Vegas and even taken to dinner got greedy and tried that ...  but i had pulled the pin on that grenade with the wife years before ...  its always best to be proactive ..  wife not happy but makes me immune from that ..   ok so  
1- idiot would email me from her personal real life name account  
2- in Vegas i know many influential people including police captains  
3- one friend asked for her name and social security number . my reply ... no you aren't going to kill her! LOL  
4- anyway i told her enjoy talking with your child from behind glass or bars ..  she disappeared.  

The provider I’m 99% sure had something to do with it was someone I met from a very reputable lady. Not knocking most of the ladies who are honest but let’s face it sometimes good quality turns sour. What about MY safety and security of my info? I mean threatening to expose all the past conversations and details. It’s a two way street. The goods ones needs to start putting the bad.

And in my case they never had the right number of my SO, they relied on old info. But, if you use real info to book it’s all out there. Nothing ever disappears from the internet.

This has been going on for months with me. Text, email, etc. he just did what he said he was going to do and left me a bad review. I believe it might be one of many more coming. he wants $900

I reported mine nobody gave a shit