but how can someone change themselves when the unhappy person never tells them how unhappy they really are?
Many times the WAW has tried to tell their S, probably in many different ways on many different occasions. Hints here and there, changes in attitude or behavior... trying to let the S know they are unhappy while at the same time, not trying to upset things, and trying to make themselves happy.
By the time they walk away, they feel they are at the end of their ropes and have no choice, and the spouse is left wondering how it all came out of left field.
She may not think what she is doing is wrong. It may in fact be what is right for her. Wrong or right is a perspective; and a judgement. So is the statement that no one will love her the way you do. From the WAW viewpoint, you aren't loving her the way she needs to be loved- she's unhappy.
Why has she turned her back on God? How do you know she has? Is God only found in church? Maybe she's actually closer to god and doesn't need a church as a go between.