Ok...gonna be blunt again. The way you sound in your posts, excusing your H's behavior (and yes you do, admit it) is typical behavior of an abused woman. Know what, I've BTDT too, with my 1st H.
You don't feel safe?!!! Woman, LEAVE!!!! Just because he isn't always behaving in a manner that makes you feel this way is no excuse to stay in the situation. Just because you feel guilt, is not reason to stay in the situation. Just because you aren't ready to jump into another R is no reason to stay in THIS R. Actually, you shouldn't even consider jumping into another R, you need time on your own. Just because he buys you gifts and brings you things, is no reason to stay in the R. Just because he's happy as long as you are there to take care of things is no reason to stay.
STOP BEING A MARTYR! Step up and take care of YOU and your kids...remember they are learning that the behavior you and your H display is OK. You respond to guilt apparantly...do you want your D to model what you are going through now? Probably not, but she's learning it's ok to live the way you are. Do you want your S to learn what his dad is doing is ok? Because he is, no matter what you tell him, you are allowing yourself to continue l iving in this stich, so your still teaching him...it's ok.
So, it sounds to me like really the only persons' happiness you are truly thinking of...is your H's. So far you haven't been able to explain to me how that makes sense. Perhaps that's because I've BTDT, I know what the other side of the fence looks like now....and I know if you could see the view from my side....you'd high-tail it NOW!