Hi g9788, welcome to PC!!!!
If she doesn't understand your depression then it's not a great starting point in her recognizing when/what support you might actually really need and she's going to be drawing her own conclusions on the support she's prepared to give, which might be completely wrong.
So maybe it would help if you could support her in understanding it a bit more/better. Perhaps talking more to her about it?? Perhaps finding her some resources?? Perhaps finding her other people experiences similar to yours?? She still might not truly understand it, but some (more?) understanding could help, right??
It might help as well if you explain the kind of support you'd like from her, give her something to "go on".
And then, it might come down to how much support/the type of support you need and what she's actually able to give. Some people can be really empathetic and supportive in all sorts of ways (and I hope your wife's can be one of those people ) some people can be completely oblivious/ignorant to what depression might be like for someone, and then there's all sorts of people in between.
I guess it depends on you and her.......but if she's not able to give you as much support as you'd like, you may decide to take what she's able to give and get more of the support she can't give from elsewhere e.g. your doctor, pdoc, T, or us on here!!!
I'd hope your wife could "be there" for you, but sometimes it can take people with "experience" to really "get it".
Anyway............again welcome to PC, there are a lot of very understanding, supportive people on here, and if/whenever you want to talk more..............

Alison