The position you're in is hard and bites! I hate to say you're spinning because you don't know for sure, I would find out. Over the years, I hate finding out the truth. But being in not knowing consumes your every thought along with effecting youself.
It sounds like there is an attraction for your W to this band member. I wonder if he knows she's married with kids. It doesn't sound like your W went out looking for an OM but may have found someone who is allowing her to life a different kind of life. Less responsiblities. It does sound like she's in MLC mode.
It also sounds like you're a wonderful father, which you need to focus on the kids. They will need to feel secure and loved doing this.
Just remember having faith in God, he is with you! He will get you though this! He will never give you more then you can handle! Although, sometimes it feels like you're at the max but ask him for help.
