Re: What to do?
You're staying at home while she goes to a bar with her friends, who sounds like she's trying to hook her up? Dude that is disrespectful.
With her being distance and your sex life sounding kind of dull, she could have already tried to step out on you but is on the prowl. There is usually one divorcee in the group that wants to entice another woman to wreck herself.
With you being so involved with the kids and the home, she's seeing you as weak. Not all women think this way but to some women, a husband who's super involved with the kids and doing more than half the household chores can come off as effeminate.
When a wife all of a sudden is taking care of her appearance and you're not reaping the benefits but are instead getting a wife that looks for silly things to cause distance, you know she's on the prowl. In situations like that, it's a fatal mistake to not to start upping your game. Hitting the gym, taking care of your appearance, getting together with male friends. Don't stay home like a freaking baby sitter, while she's out getting her freak on.
You can keep playing James Bond for more evidence but if something is close to happening, you may be to late to stop it. Personally I think you have enough to confront her. But it must be done with a firm hand. Don't be cowed by her crying that you're invading her privacy or that you're being controlling. Your family is on the line. They need a strong man to fight for the family because you're wife is on the path to destroy it.