Spouses are usually considered to own property 50/50, unless you have some other agreement. 

Adjusted cost base is usually the cost of a property plus any expenses to acquire it, such as commissions and legal fees.

Adjustments can include items such as capital expenditures. If you’ve already included this amount in your entry for the adjusted cost base at the time of disposition, leave this field empty.

Additional information can be found by visiting the CRA's section on adjusted cost base