Your wife is in the throes of MLC. She's depressed, she has low esteem and worrying about mortality. All things the MLCers suffer from and need to work on. If she opens up and wants to talk, listen to her and validate her thoughts/feelings.
Now, here's the thing, if your wife suggests going to a movie and/or another activity, unless you are busy or don't feel well, I would accept now and then. You need to remember that right now, she is searching for answers and the only way to find them is to test the waters. You need to keep your expectations at zero and try to look at her as just a friend. Depression numbs their feelings and while those childhood feelings of resentment, hurt, etc. are bubbling to the surface, all of the good things have been stuffed down. So, please do not take what she says about her feelings as a personal attack on you...this is her journey and until that depression lifts, her feelings not only for you, but all of the goodness in her life has been put on the numb stove for a bit.
If you want to go on a date w/her then accept her request once in a while. You might discover that she will be more open to talking a bit more freely when she's in a different environment and feels safe to do so.
Keep your expectations at zero, treat her as a friend, listen, but don't offer advice unless she asks for it, dig deeper for patience and keep the focus on you and your GAL activities.
Sit quietly, the answers will reveal themselves when you least expect them to. The past is gone, the present is a gift and you need to focus on today, allow the future to reveal itself when it is ready.
