Allow me to humbly suggest some things to think about:
1. You are still having an affair. It never really ended. If you didn't cut off contact completely, you are still emotionally enmeshed with the OM. And you can't help comparing your husbansd with him. And if the OM is "100% comitted to his own marriage", then what's he doing on the phone talking with you? Aside from your marriage issues, you are not helping the OM with his by being emotionally enmeshed with him. You are hurting his marriage. This connection you have with OM will prevent you from having true honesty/intimacy with your husband, and it's leaking all emotional energy from your marriage. It's not simply "just" a connection: you are in love with another man and having an emotional affair. You have been having an affair for 4 years and haven't told your husband about it.
2. I think if you want your marriage to work, you need to end all contact with that man.
3. I think, perhaps, telling you husband might lead things to a new level of honesty. It might be a wake-up call for him to really start to change, or it might end your marriage. Either way, you will have closure. You end up with either a good marriage or no marriage, rather than an unfulfulling one where you are hiding an affair from your husband. IF you tell him, he may leave you, and then, that's it. If you tell him, he may ask you to end the relationship with other man and you may refuse, which will probably end the marriage. Or, you can tell him and offer to end the relationship with OM with the hope that you two can work things out. Either way, be honest, it will lead to change. So, I would say, tell him.
4. Part of you wants the marriage to work. Maintaining an affair is working against you. Remember -- you never really ended it. Read about emotional affairs. Google the subject -- they are as deadly to marriages as physical affairs.
5. I don't know what your religious/ethical position is. In almost every religion or philosophy, having an affair is considered a lack of honesty and integrity and a form of betrayal. Do you want to live that way? This doesn't mean that you are not getting good things from the OM. In the language of St. Augustine, there is no such thing as pure evil. Even a thief steals in order to enjoy the benefits of what he stole. Does this make any sense? Even Jesus when he was tempted, was tempted with things, under different cicumstances are good: satisfaction of hunger and the excericize of power. So, there's no question that the OM provides you with some legitimately good things, the question is, how do you feel about the fact that you are taking them from his wife, and that you are lying to your husband?
It all boils down to what do you want? A life of honesty or a life of deceit?
I say gp for the honesty. You've tried hiding the affair and trying to "change" your husband -- it doesn't work. Try telliing the truth and see if you can't really work towards a good marriage.
