That sounds really good! And you know what? If she doesn't ask any questions about what you and the kids are going to do, I'd just keep quiet about it. You see, she is focused on herself instead of her H & children. So if she doesn't show enough interest to even ask.....don't inform her of your plans. Then you can surprise the kids! But of course, if you have to leave, etc. before she does.....
The kids will be so excited and will be telling mommy how much fun they had spending a day with their dad at the beach.
It's good to have some kind of "plan" tucked away in your mind, so if you need to find something to do at the last minute, you can fall back on that plan. Staying home and doing things around the house or with the kids is fine, but it can also become like a "trap" if you do it to the point that you aren't going out and doing things just for you. Know what I mean?
Another reason to have a back-up plan is so wheneven your W springs some plans of her own and automatically thinks you'll babysit, that's when you tell her "Sorry, but I've made plans and you'll have to find somebody else to keep the kids". She won't like it, but after a few times of this....she'll learn to respect you and at least "ask" if you have plans before she just assumes you'll be home.
It will seem odd to go out and leave your W and kids at home, b/c being a family man....you aren't use to leaving them behind. The point here is that she sees you going out and having fun and building a life "without her" in it. That should stir her curiousity a little bit! Plus, becoming more involved in activities should help to make you very interesting.
Remember that you show good manners when you're home and speaking to your W, but you treat her as if she was a co-worker or a clerk at a store. You do not ask questions about her day, b/c she sees that as pressure (especially if she's having an A) and....you aren't to give the impression you are even interested. You don't start conversations with her. If she wants to talk then you look into her eyes as she speaks (women need that--and she'll know you are really paying attention to what she says), but you let her talk. If she asks questions, you keep your answers short. DO NOT get into R discussions b/c it will lead to an argument. If she says something about the R, then you can nod your head or say, "I'm sorry you feel that way". But, don't get into it with her.
A big thing is to stop making contact through-out the day with her. Unless it has something to do with the kids or an emergency....no contacting. And, don't use the kids as an excuse to contact her. I see LBH's doing that a lot. It is obvious to her. Your WAW may be in a fog but she can see through a lot of things about you b/c she knows you so well.
It is not about what you feel should work in your M. It is about doing the work that gets the right results. Do what works!