It is always a shame when one person seems more invested emotionally invested than another. Unfortunately that seems to happen a lot. it is also very hurtful when one person starts to need a lot more social activities and possibly include single people, especially those in bars. It sounds like you are tolerating emotional abuse that I don't encourage men or women to tolerate. Along this with that you are growing apart and have less in common. That doesn't mean she is having an affair but it may feel that way. The only way to find that out is through her, her activities or people she knows. Just be prepared that you are ready for the answer!
As far as you and your options, you can become the party guy but that would just be pay backs not who you are. You can make your feelings clear but she may not listen. You can focus on your children but that doesn't mean you will have a healthy relationship. So your choices are to move on and find happiness or tolerate mental abuse. I usually say to try counseling but you have tried that so now your choices must be much more serious. Only you can figure out how to address this and salvage your time with your children. Do what you feel is right because name calling is unnecessary
What do you make of her wearing her deceased father's varsity ring on her necklace and losing her wedding rings? It feels that is a sign of something unhealthy -- not seeking a conclusion, but just a preliminary impression about what wearing a ring for the first time after over 6 years since his passing. . .