Hi and welcome to the forums.
I cannot speak for your wife. All I can do is give examples from my own life. In my own words there appeared in the your wife's words words some contradictions... for example, missing you but wanting to be alone. With depression I may not want to be around people. At the same time I know that can be good for me.
Why would I want to be alone ... ? I don't want my wife to see my like this. If she sees e like this she might not want to be with me. Shame. Embarrassment. Unsure how my partner might react.The walls can be how we have learnt to deal with situations. At the same time I can also see how much you care for and love your partner.
Perhaps these are some things she is working through with her professionals.
I would also say that without any depression the last 12 months would have been quite stressful for anyone.
There are pages on the beyond blue web site for partners which you might want to look at. It is also OK for you to talk to a professional as well - to talk about the situation and work through your thoughts and feelings. You could also get perspectives from family and friend ... in a mindful way such you dont overstep any boundaries set by your partner. I hope that makes sense.