The first thing I'd do in the writer's situation is sit down with the spouse, and take some time to go over the list of things they thought they needed badly. For each item on that list, figure out what they've been doing in the absence of said item and determine whether or not they can continue coping in that way. If they think they can continue coping for a while longer, then the item isn't needed THAT badly; money that would've been spent for that specific item can instead go towards saving up for the new tablet. On the other hand, if the determination is that the couple can't continue coping, then there is a genuine need that should be taken care of. Money should be prioritized to addressing genuine needs first before saving up for the tablet.

Unfortunately there is only limited information about the writer's situation. We don't know what kind of disability they have, how it affects their everyday life, if there's stuff in their home that's broken and needs to be repaired, etc. If more information were available, respondents to this post would be able to provide more specific advice or guidance.