Your pastor has some good advice! I was going to tell you essentially the same. You don't need to celebrate your anniversary, but doing something small like some flowers and a card or something just lets her know you remembered the day, you're not ignoring it. That's what I did and that felt good to me. Ignoring it would have just felt wrong to me.
I think you should only go on this trip if you are sure that you can have a GREAT time without any R talk or any kind of pressure. If that's not the case, it might just worsen the sitch.
My W too was in a pretty severe depression. Seeing your W is about the same age, as well as numerous others on this site, I came to the conclusion that this 35 to 40 age seems to be prime time for this kind of thing. In my case, I have seen improvement over the last couple of months. I see more and more of the "old" W as I knew her for years. I too was worried for her, but I have read in more than one book and was told by numerous people including the MC that, as an outsider, you cannot get someone out of a depression. They have to get themselves out. Any "help" you're trying to give will just make matters worse. So I just tried to give her as much space and time as she wanted. I can't say that my case is a success, but I remain cautiously optimistic, especially in light of recent events.
My advice for you would be to try and walk that fine line between being there for her when she needs you (keep her from going deeper down the depression path) and being detached. In my mind, it felt like being a best friend. You would go back and forth between being really involved and concerned and being distant, doing your own things. I don't know if this makes sense to you, but that's how I tried to keep myself on track.
