Spousal support is paid based on the length and nature of your relationship. A disability will usually not affect your entitlement to support, but it may affect the length of time you are entitled to support for. Spousal support always depends on the specific facts of the situation. Did the parties cohabitate for a long period or a short one? Did one spouse always support the disabled spouse or did they mostly get by on their disability payments? Generally, if a person is in a relationship where the parties cohabitated for at least 5 years some support will generally be payable. Spousal support typically lasts for between 50% and 100% of the length of cohabitation.
In the case where one spouse is permanently disabled, support could last longer than in a normal case but again this will depend on the facts. If the disabled spouse was already disabled before entering into the relationship and the relationship was not particularly long, then there is less of an argument for long term support and vice versa.