This was a shared account between me and another guy who was also curious. I know there is absolutely no way for my wife to know my true intentions and that I did influence her behavior.
This is another example of you taking responsibility for your actions, something she has not done. The problem here is that your wife used your remorse to justify her cheating on you and to bully you with a false holier than you control over you and your marriage.
To better evaluate this matter, let’s separate what each did, and look at the transgressions on their own merits by asking the following questions:
1) If you found out that your spouse had a shared account with a friend on a dating site for 3 days where you had no evidence whatsoever that they ever acted on it, where they claimed that he and the friend never had the intent to cheat, where in remorse they accepted “as part of the repercussions for betraying” your trust years where you “constantly controlled everything” they did, who they “hung out with”, “phone, internet, email and monitored” whereabouts, and where they did not have a history of lying to you, would the average person seriously consider divorce based on only this? I would say no.
2) If you found out that your spouse had an emotion affair (EA) where they exchanged and saved sexting photos with a member of the opposite sex, and where your spouse has a history of lying to you “about a lot of things”, would the average person seriously consider divorce based on only this? I would say yes.
3) If you found out that your spouse secretly stayed overnight at the home of a member of the opposite sex that you did not trust while lying to you about their whereabouts, where the reason for the lie did not make sense if the replacement story was true (why lie if all 3 girlfriends slept over?), where the story of why she did it did not make sense (why did she wait until morning to take a cab?), where their story of where they slept did not make sense (3 on a couch?), where she and the other man that you do not consider a friend of your relationship have a relationship that includes regular non-work related contact throughout the week (remember the history of an EA), where your spouse has a history of an EA, and where your spouse has a history of lying to you “about a lot of things”, would an average person seriously consider divorce based on only this? I would say yes again.
Bottom line is that the average person would not seriously consider divorce based on what the OP did, but the average person would seriously consider divorce for either of the two things that the OP's spouse did, and more so if you consider she did both divorce-able things. In answer to your question in this threads title "Is it bad enough to divorce over?", for her no, for you yes.
It takes from 3 to 5 years for a betrayed spouse to deal with a full on affair by their spouse; your 4 years of paying your dues for the dating site matter is more than enough time considering you never actually cheated; your dues are more than paid and she does not get to bring it up anymore. If you still want to give this marriage a try, she needs to be willing to start paying her dues for her far more serious martial transgressions without bringing up the dating site matter as an excuse. Again, your dues are paid, her's are not.