She admitted that she loved this guy and is confused.
I'm sorry that you're in this situation but glad you found us. For starters cheaters lie, a lot, right now your WW is not remorseful, way too soon for that, she just regrets getting caught, now just because you now know doesn't mean the A won't continue deep underground or reignite in the future, here's some of the basics:
1) FULL EXPOSURE: Expose the A with ALL family and close friends, and of course OBS (Other Betrayed Spouse) if any, it needs to be done WITHOUT WARNING for maximum impact, your kids already see there's something very wrong in the house, they were betrayed too, tell them the truth, they don't need the gory details, just that your WW loves her boyfriend. Is POSOM married has a girlfriend, find out (don't just take your WW's word for it) and inform her, again without warning your WW, if she complains that means she's still probably in contact with POSOM.
Full exposure without warning typically kills the "beautiful, romantic and exciting" aspect of the A and replaces those with pure shame and embarrassment, the more she hates the A, the more she will hate POSOM and therefore could help her get out of the "fog" sooner, let her deal with the explanations and apologies to the children and your/her parents and/or other relatives and close friends.
2) NC FOREVER with POSOM: She already sent a text to him, he needs to be blocked everywhere, phone, social media, etc., she also needs to tell you if he attempts to make contact again in the future.
3) She needs to offer full on demand access to her phone and all electronic devices and passwords, FOREVER, no questions asked.
4) Consult a D attorney to know your legal options, knowledge is power, while you're at it, ask about a postnuptial agreement that's enforceable in GA, you need to be protected in case she cheats again or you decide at some point this was a dealbreaker for you.
5) Demand she gets tested for STDs, full panel, she admitted she loves POSOM plus they have a history, so the likelyhood she used protection is slim to none. Yes, she's been playing russian roulette with your health too.
6)Demand she writes a complete timeline of the A, then have her read it out loud to you, it helps with remorse and helps you know what you would need to forgive (not forget).
7) Demand a polygraph, make a list of questions you need answers to, polygraphs typically allow less than 5 questions but she doesn't know that plus she won't know which ones will come up on the test, even if she agrees, make her go through with it, it helps with remorse and you may even get what's known as a "parking lot confession", one of the questions should be if there have been others, this may not be her first rodeo.
8) She needs to go to IC with someone who specializes in infidelity (very important), forget MC for now, it's typically a waste of time and money at this point.
If she refuses to any of the above, then just file for D and have her served without warning (you can always stop the process if she comes around), if full exposure and D papers don't shock her back to reality then nothing will, but either way you will be on your path out of infidelity.
Keep posting frequently, the collective wisdom of SI could help you go through this difficult situation, we've "seen" it play out thousands of times here and in other websites, every case is different but cheaters typically follow a similar script.