I'm not one to give advice...I'm new at this myself, but here is how I see it.
A common theme I see from the MUCH more wise people on this board says that an OP is just a symptom of the problem, not a cause. So some say don't dwell on it or worry about it, because yes it will make you feel worse. Which is true But I feel its also very necessary to know.
Now in my situation my found out my wife was texting a boyfriend from her teenage years, but just to talk as a friend. I do believe her because there was never CALLS to his number on the phone, just texts. Plus she lives with a friend but I don't think he would ever be over because I basically still always know where she is (she calls me several times a day.) I don't believe my wife would do that to me. How do you feel? People say you usually have a gut feeling when something is going on. Do you have that feeling?
Now back to why I feel it is necessary to know is because what if your wife, or our wives, are cheating on us? We try and try to DB and its not working, and we give in and go for the divorce. Is this something you want to have on her in the divorce? I don't know how well the laws work but wouldn't you get more out of an AT FAULT divorce? Well someone cheating on you is enough grounds. So here is how I see it bottom line, and maybe this is because I am in such an angry place right now. If my wife was cheating and we ended up working on things and her OM was a symptom, I could forgive her for that. If she left me for someone else and that was the REASON, I would want to make sure she has to pay for that in court. Thats all just IMHO.