The partnership and free time issues are going to be very specific. Everyone is going to have different needs. For example, some businesses require 24/7 service, and/or being able to go more than one place at a time, and, some people need time off to recharge/not get burnt out.
I would not say to never have a partner, but, as mentioned, partnerships can sour if there is insufficient leverage to level the work loads and drive the business to more than double its cash flow past what one owner could do. Doubling the cash flow is only a break even point if its being split two ways.
For many businesses, and for many owners, never being able to take a vacation/time off = unhappy spouse/progeny = you are always working. Some relationships will survive that (Family business, all happily working together for the mutual good), and some will not (You're never home/friends and family think you love the business more than you do them, feel neglected, etc), or, the family member(s) see your business as an entitlement for them, and don't feel they need to "work", just show up, etc....and act as expensive dead wood.
Some businesses are of the nature that you CAN simply tell a client you're not able to help them for a few weeks...and, they can wait. If you're fixing leaking roofs, mowing their lawn, a mortician, or plumber, etc, they may need to call your competition. Having a partner means that 1) You can go on vacation/take time off, take a sick day if needed, because the other owner is still there to run things. 2) You have given another person half your business, and, they may try to take it from you later, or, make decisions you disagree with that hurt the business, and/or that you disagree with that help the business. IE: Their involvement is a crap shoot. (On their side, they are deciding if YOU are a risky partner as well, etc..)
So most new businesses tend to have the owner do EVERYTHING, and work 48 hours a day 14 days a week to get it all done, until the business gets up and running and they can start delegating some responsibilities. Some NEVER get past that point, and, some go bankrupt trying, and, some actually succeed. The key to success is cash flow though. If you have no kitty to draw from, you have a rolling kitty that you feed/drain hand to mouth. That means that if under capitalized, one slow period, or one fatal mistake, or one injury can kill your fledgling business. Getting working capital is probably a main reason people find a partner in the first place....one provides the money to buy equipment and pay staff to get things going, the other provides the technical expertise. The trouble comes later, when each feels THEIR contribution was worth more, and, wants something in return for the difference to compensate.
The compromise is to hire a manager who can run things when you're not around, but who you pay a salary/compensation of some type...as opposed to giving a percentage of ownership....or, give a lower percentage of ownership to, say in terms of stock as opposed to controlling interest, etc. The downside is that, especially for a new company that might not have developed the cash flow required to pay a manager in addition to supporting YOU...you may not be able to afford to hire people of the needed caliber, which can include those candidates being able to fog a mirror, etc. Going to the bank/venture capitalist, etc...for a loan, is a popular way to get start up capital...but, they want a return on their investment....and, if there's no cash coming in, its your house, etc, that might be used to pay them back.
Living small, even when things look like they're going well, so that if things change (Recession/depression, regulatory change that cripples you, losing key client(s), new product from a competitor you can't match, family illness/emergencies, etc), your monthly nut is easier to crack/less likely to break you. The lower your overhead, the less you NEED to make every month to pay it...and the more you can sock away the difference. If used to getting a salary, getting paid randomly can be hard to adjust to for some people, and, you need to essentially give your self an operating budget for the business and home life as well....and sock away the left over to get you through the lean periods, rather than "celebrating" with new cars and larger houses etc...or, appeasing the neglected family members, etc. They typically want your time more anyway....and that's the most expensive gift of all.