Should my spouse be involved in the decision to sell, even if they don't work in the business?

Often yes, and not just as a matter of courtesy — a spouse who has never worked in the business can still have a legal or financial interest in it that affects the sale. If the business, or its value, grew during the marriage, it can still be relevant to how property is divided under Ontario family law if you were to separate, even if it's held in your name alone, and if your spouse is a shareholder, a guarantor on business debt, or has signed anything related to the business, their consent may be needed to actually complete a sale.

The trap is assuming that because a spouse isn't operationally involved, they have no stake in the outcome. Proceeds from a sale, how they're taxed, and how they're shared can matter enormously to household finances, and to how the business's value gets treated if the marriage were ever to end.

Rather than guessing at what role your spouse's involvement should play, it's worth having a business lawyer, and if relevant a family lawyer, clarify what legal interest they actually have in the business and the proceeds before you're deep into negotiating a sale with a buyer.