Hi nitaf, I just read your post and thought I'd jump back in here.... The most important things to consider as you decide on sending the letter are: 1) what do you hope the letter will do?
2) and the classice DB yardstick, will what I'm about to do move me closer ro or further away from my goal?
that said, I have to caution you that I am afraid you will be disappointed in the results you'll get from the letter....my perception is that you are kind of hoping that if you express how OW's actions are affecting you & your family, that she will "cease and desist". I believe this is very unlikely to be the outcome, and that it will give your H more fuel for his "fire" and cause you more distress. My experience has been that frankly OP's know darn good and well what they are doing and how it affects people, and they either (a) don't give a damn or (b) get some kind of perverse pleasure out of it. either way, anyone who would prey on a person who is suffering in a difficult marital situation (and that's exactly what it is, preying) is either a shark or a pirranha, driven by their instincts, and as such, I believe they are totally immune to, if not incapable of, reason. If reason had any effect on them, they wouldnt be doing what they are in the 1st place. If OW is the type who gets pleasure out of it (I'm convinced they are out there), you will really be playing right into her hands and rewarding her behavior. Behavior that works (is rewarded) is behavior that is repeated..the letter could actually backfire by making her more determined.
I hope this doesnt sound too harsh, I'm just afraid sending the letter will do you and your sitch more harm than good...I can just see OW running to your H with it (I know that's what would happen in my sitch) and H having more reason to justify his actions/defend his position. just IMHO....I sure encourage you to get more opinions than mine before you send it, and think long and hard....
what would be the worst case secenario that could result from you sending the letter, and how will you handle that?