The corporate share structure lists all shareholders including the number and class of shares each owns
If there is only one shareholder with 100 Class A voting common shares, the share structure is simply 100% owned by that person.
If spouses each own 50 shares, the share structure would be 50%-50%. These 50 shares could be both Class A, or one spouse may own 50 Class A voting shares, and the other spouse owns 50 Class B voting shares. Class A and Class B may be set up with the same rights and powers (just shares in different classes), or they may have different rights and powers, such as voting and non-voting.
Dividends can only be paid to shareholders, and dividends are always declared and paid to a class of shares, not to a shareholder.
Spouses can also own 50 shares of the same class (Class A voting shares). This just means that if a dividend is declared to Class A Shares, each spouse must take the dividend based on their pro-rata ownership of that class of shares.
If a $100,000 dividend is declared to Class A shareholders, and Tim owns 60 Class A shares and Joan owns 40 Class A shares, Tim must claim a $60,000 dividend, and Joan must claim a $40,000 dividend.
What's the benefit to owning different share classes? If Tim owned 60 Class A shares and Joan owned 40 Class B shares, they would still be 60%-40% owners in the company, but they would have the flexibility of whom to pay dividends to and how much. If they wanted, they could declare a dividend only to Class B shareholders.
If there are multiple shareholders that are arm's length individuals, the share structure and share classes need to be clearly thought out. A Unanimous Shareholder Agreement is probably a good idea. Consult a lawyer if you're in this scenario.