If she continues contacting the other man (OM), then you'll likely have to expose the affair. Tell her family, your family...contact the OM's family in just the manner you have considered. The intent in this is to make this public...it prevents them from carrying on this illicit behavior in secret, which was part of the thrill in its own right
This is something Owl posted above. Exposure is part of Plan A and needs to be done strategically. Exposure is done mostly in one swoop. You come up with a strategy that we can assist you with. You need a list of who you plan to expose to and what you intend to say. You DO NOT discuss this or threaten exposure to WW or OM as this may give them a chance to minimize it's effects. If they are forewarned they will likely call or tell their friends and family to expect a call from this lunatic jealous husband. They will paint themselves as just "friends" to whom you are overreacting. Thus do not give the enemy your battleplan.
Do you fear exposure??? Definitely. Your wife will go through the roof...however, affairs thrive in secrecy. Your marriage can survive her anger but it can not survive an on-going and ever deepening affair. I for one did not expose to my family as they had no influence over my wife's actions and would be of no use busting up the affair. So your list should include only those persons that may have an effect on the affair. If your mother is close with WW then include her...if not, don't.
You may consider doing exposure in two stages. Immediately do the persons closest to WW and OM. His and her family and friends and especially OMSTBXW (OM soon to be XW). The conversation with OMSTBXW is especially important as you want to get as much dirt on OM as possible. Try not to reveal this information but it can help later when pointing out his flaws to OM or assist in any custody battle. The 2nd exposure will be done later, without forewarning, practically telling the world.
On that custody note, I am a part-time tax attorney (I own businesses now also). I am not a divorce attorney...but I often advise on these boards about protecting your backside. You should never discuss divorce while in the Marriage Builder plan. You do marriage and that is your only focus as far as your wife is concerned.
However, behind the scenes you must protect yourself and your children. This includes at least a consultation with an attorney. Then when your wife discusses divorce, if ever, you direct her to your attorney. Let the attorney's handle any divorce discussion.
You must also begin a journal or two. One journal may be for your personal feelings, pains and strategies. Include the things you find on here which strike you. The 2nd more important journal is the custody journal. In it you must document everything you are doing and she is not for your children. For a man to obtain primary custody of his children you must begin immediately compiling the evidence necessary to convince a judge you are the responsible parent and custody with you is in the children's best interest. You are not using custody as a punishing tool but obtaining custody will certainly be a magnet for pulling your wife out of the fog of an affair. You may think I am jumping the gun here but what can it hurt to start thinking of these things right now. You need something to occupy your mind with now anyway.
Finally, you are not 2nd best to this guy. Try not to keep doubting yourself. These situations have a way of bringing up any and all of those latent insecurities. This is not your high school girlfriend dumping you all over again. Your wife was chosen for you by God. She is God's perfect gift to you and you are #1 in God's eyes. Do not doubt yourself. Stay strong...you will make it...with or without your wife...you will make it. Almost all marriages survive affairs (maybe 90%) and most marriages end up as better marriages after these situations are resolved. I am now in a better marriage. April 26th was the worst day of my life but slowly it is become one of the best days of my life as well.
Good luck,
Mr. Wondering
P.S. - So I suppose you'll be rooting for the Cowboys this coming Sunday against my Detroit Lions. Despite how much the Lions have always sucked we seem to always beat you guys up...hopefully this week will be more of the same.