Second that book. Not all of it applied to me, but too much did for me to deny.
D&C, you can't control your emotions. Just accept them, learn to roll with them, but don't let them change your actions. What you do, what you think is based on your values, who you are. Not how you feel. Today I'm as hot as a pistol at my W, but I'm not going to let her see that. I'm going to smile when she comes home, set one hell of a boundary that I should have set 11 years ago, then go to sleep.
Being strong isn't acting like John Wayne and not having any emotions. Spock doesn't live here. We do. Being strong is choosing the Right Thing To Do, even when it hurts like hell. It's sacrificing for your family when needed, for friends, and yes even sometimes for a STBXW when it's the right thing to do.
What we're all learning here is how to know ourselves enough under incredible stress so that we can determine What The Right Thing is. This is our crucible.