I'm sorry that you had to join this club but glad you found us. Your WW (Wayward Wife) is NOT remorseful yet, she just regrets getting caught and had the AP not emailed you, it would still be ongoing today, she did not confess and is still holding lots of info, we call it TT (Trickle Truth), right now she's probably still grieving the loss of her boyfriend, you need to EXPOSE her A with ALL family and close friends, she need to apologize to them too for her huge betrayal, just because you found out about it, doesn't mean it won't go deep underground or resume in the future, she's now a proven cheater and a liar, don't take the blame for the A, problems in the M you own 50/50, her A was 100% her fault and her DECISION, she ChOSE to cheat and lie to your face literally thousands of times. Here are some of the basics steps I suggest you do and that are pretty much the concensus here on SI:
1) Demand she gets tested for STDs (you should too), no they did not use protection and even if they did, some STDs can be transmitted via saliva (kissing), also a pregnancy test is in order if she was not on BC (Birth Control).
2) She needs to offer FULL on demand access to her phone and all electronic devices and passwords, you might want to download Fonelab to recover deleted texts and emails.
3) Expose her A with All family and close friends, this is a VERY important step, she needs to own this and apologize, she needs to be embarrassed by her A and not remember as "something beautiful and romantic" but rather as the one thing that destroyed her reputation and integrity, the more she hates the A, the more she will hate her AP (Affair Partner) and the less likely she will cheat again in the future. Don't warn her about it, just do it, also find out if AP is married or has a GF, if so inform her about it too, just because he told you doesn't mean OBS (Other Betrayed Spouse) knows.
4) Consult an attorney to know your legal options and to see what D would look like, at a minimum, demand she signs a postnup in your favor (no alimony/spousal support or half of your pension) in case she cheats again in the fuutre or you later realize this is/was a dealbreaker for you (which is ok too).
5) She needs to send and NC FOREVER letter to AP, and any friends who knew about/covered for and/or enabled the A need to go too, they're not friends of the marriage.
6) She needs to write a complete timeline of the A, you may even have her take a polygraph test after that and one of the questions should be: "have you had other inappropriate relationships with anyone else besides AP since we've been together" ? yes there's a chance this was not her first rodeo.
7) She's in self preservation mode now, don't believe her words, watch her actions, did I mention CHEATERS LIE ? yes a lot.
8) She needs to go to IC to find out her "whys", how did she give herself permission to cheat on you and keep doing it for such a long time, how she came home and looked you in the face after having sex with AP, her betrayal was huge, DO NOT RUGSWEEP THIS to "move on", if you do, you will most likely wind up here again in the future.
9) Keep posting, the collective wisdom of SI can help and guide you through this difficult process, we've seen it play out THOUSANDS of times here and other websites.