1. Since she is behaving differently since last few days only, it will be prudent on your part to wait for some time, may be even few months to enable her to feel the life without having a proper family.
2. It is not unusal that couple suffer mid life blue at te stage which you are now passing through and they behave in unusual manner.
3. Time is the best medicine in such cases which you should allow her.
4. One very important aspect herein is that if she expresses more s8xual, attention on her, any negligence on your part to attend to her may induce her to think that you are no longer interested on her physically and it might force her to go in mental depression.