If you are going to seek a counselor, be sure to find someone who is a solutions based therapist. That is really, really important.
You need to have a talk with your wife and ask her if she wants to work with you on saving your marriage. Don't bring up who did what to whom, or why your marriage has gotten to the state that it has. All the two of you need to do right now is to decide if you are going to work together to save your marriage, or if you are going to work together to end it.
Once you've made that decision, then you can start finding solutions. If she wants to dump on you during this conversation, then try to let her without getting defensive. Just validate her, and listen. Your turn will come. But then once she is done dumping, ask her again if she is willing to work with you in saving your marriage. If she doesn't know, then give her a certain period of time to make her decision. Say, okay, take the next three weeks to think about it, and let me know on such and such a date what you think. Make sure you give her enough time to think it through, but also give her a deadline so you don't hang out there in limbo.
You also need to decide what you want. Take all the time you need as well. But in order for either of you to do anything constructive, you must first make this decision.
