"Part of me wants to go talk to her DH. Sound him out to see if he has suspicions...but I don't want to break up another family if I am wrong. I don't want to destroy DPs friendship if I am wrong."
I'm sorry, but a big part of me thinks that it's wholly inappropriate for DH to be super special friends with another mans wife...
Where I've been living the last 3yrs, there is one supposedly good rule. That married men and married women do not speak to each other unless they are married to each other.
I say supposedly, cos of course Hypocrisyland that it is... DH has had 19 (yes you read right.. nineteen) married women, mostly married to his friends calling, texting and going round to the flat we used to share, offering themselves to him. Cos I'm back in the UK and his needs are not being met...
Thank GOD it's backfiring on them, he's more determined to leave that nuthouse than ever.. and they are all individually on a warning, contact me again, and I'll tell your DH... So far all is calm.
I think if your gut is trying to tell you something, then you ought to listen. I think if there IS a friendship at all between this woman and your husband, and you know her DH, then perhaps you ought to have a chat with him. If you are wrong you are wrong, but if you are right, it stops the rot right now. Unless of course you would prefer the ignorance is bliss approach.
Try the sim card readers, and whatever else you can, then speak to her DH. He may not have noticed anything, men can be a little clueless on subtleties, but you never know!