You are too late to nominate as you have to do that within two years of the second or subsequent acquisition. In any event, at present you have no ownership of the second property (its in your wife's name), a married couple can only have one main residence between them and such an election would not be backdated 11 years. The government plans to scrap the ability to make a main residence election due from April 2015 due to abuses of the rules.
How existing main residence elections will fit in with any scrapping of the election if that happens remains to be seen. As we approach a general election and the budget only takes place a couple of months beforehand, some government fiscal plans may be dropped in the "wash up" before the election which is where the political parties agree to allow some things through by consent and others to be dropped by consent.
If you moved into the property and made that your main home, you could not simply sell it a few months later to capture the last 18 months of ownership as a tax free period as such action will probably be attacked by HMRC as a pure tax avoidance ploy. You would need to be looking at living in that property for at least year and in any event, if the main residence lelection is scrapped, the CGT postion would be based on the facts of the case, ie where you lived and for how long.
In order for your CGT position to mirror your wife's so that you get any main residence relief and letting relief if approproate based on her occupation of the property she owns, you would need to be living in it as your main home before it is put into joint names. Take a look here
for more information on that. This probably doesn't apply to you as the property appears not to be one your wife owned before you maried.
There is more on the main residence and CGT here
I hope this helps but let me know if you have any further questions.