Where as if W says "I'm so worried about affording somewhere nice to live" I could answer with " i understand that you are concerned, why do you think you can't afford somewhere nice?"
Or have I got that wrong??
That 2nd is probably not the best example because it's probably not a real strong expression of feelings, and strong feelings is where validation kicks in. IE, if her mother were in the hospital and she said she was worried, that is DEFINITELY a time for validation. But if she's just mentioning in passing that she's not sure y'all can afford something then it might make more sense to try and talk that through to determine whether or not you really can afford it. Does that make sense?
To put it another way, let's say she said "I'm worried about affording somewhere nice to live" and you said "OK let's look at the finances" (this is not validation, but may be appropriate in this case), but then after you looked at them you did indeed determine you cannot afford to move. Let's also say that your current house is perfectly adequate. After this determination your W says "I'm upset". THIS is the time for validation. Your inclination might be to say "but our current house is great, there's nothing to worry about!" That would be invalidating how she feels. Instead you should say "you do sound upset, how upset do you feel?" Note that you should never respond with the old fall-back "What's wrong?" because it's a loaded question- it implies there's something wrong with her and thus the only safe answer for her is "nothing" (sound familiar?) Anyway, she might reply with "I'm VERY upset!" after which you can ask her further questions about how she feels.
Retrouvaille is all about teaching how to communicate emotions to each other, and the goal is simply to understand the other person's emotions- how strong they are on a scale of 1-10, what other life experiences the current emotions can be related to, even what color the current emotions makes the person think of. The goal is to accomplish this with no attempt to fix/ explain/ justify/ agree/ disagree/ etc. RetroV will really show you how incredibly hard it is to do this because we're simply not brought up this way, but how rewarding it is when you can do it properly. People hear these techniques and think there's no way they work, but they really do. When you seek to understand the feelings of others you make a deep connection with them.