vidya, your assessment is correct. It is clearly mentioned that this applies to married couples as well.
Below text forms a part of your guidlines notes.
This category has been created to recognise the contribution skilled spouses, civil partners, unmarried partners or same sex partners of those successful under HSMP can make to the UK economy given the entitlement to work in the UK.
50. In order to score in this category, you must provide evidence that your spouse, civil partner, unmarried or same sex partner is educated to degree level (e.g. BA or BSc) or an equivalent vocational or professional qualification. Alternatively, you can provide evidence that they are currently or have previously been employed in a graduate level job (for definition see work experience section). Your spouse, civil partner, unmarried or same sex partner must accompany or join you in the UK. In addition your spouse, civil partner, unmarried or same sex partner must not already have been granted settlement (permanent residence) in the UK.
51. In addition, you must provide evidence that you and your partner have been living in a relationship of either marriage, or a relationship akin to marriage, that has subsisted for the last two years or more before the points can be awarded. (see paragraph 37 of guidance notes for more details on partners)
52. You must provide three pieces of evidence, from the list below, addressed to you and your partner to demonstrate that you have lived in a partnership at the same address for the last two years.
53. If you are married or have entered into a civil partnership, please supply your marriage certificate or civil partnership document as one of the pieces of evidence to confirm your relationship.
54. For example, if you and your partner have been living together since March 2002 you should supply a piece of official evidence addressed to you both, at the same address from March 2002 (if married or in a civil partnership, this could be your marriage certificate or civil partnership document to show when you started living together), a piece from 2003 and a piece from March 2004.
55. However, if you are unable to provide sufficient documents that are jointly addressed you should provide four pieces of evidence from the list below, in a combination of some addressed to you and some addressed to your partner to cover the two year period.
56. In order to provide evidence of your relationship you must supply documents of the type described below as evidence that you and your partner live together.
* telephone bills or statements
* gas bills or statements
* electricity bills or statements
* water rates
* council tax documents
* local social services department correspondence
* local health authority correspondence
* government department or agency (e.g. Inland Revenue,) documents
* bank or building society letters or statements
* credit card statements
* insurance certificates complete with address
* mortgage statements or agreement
* tenancy agreement