Should I have co-founder in my business? Questions I am asked many times.
My response in 99% of the time is NO. Here is my reasoning:

i) different views
Even if you discuss same idea at the beginning and you seem to agree on everything, later on you may find that you are wasting enormous amounts of time and energy on discussion if this button should be red or green. We all see world differently and last thing you want is to spend energy persuading you co-founder about your point of view.
If you need feedback and advice, have your circle of friends help you. You don’t need co-founder for that.

ii) working ethics
Everybody has different levels of what I call “working ethics”. That means how hard and consistently you work. When you are more into your project you may realise that working ethics of your co-founder(s) is much lower than yours. Which is not good. You want to work with people with equal or higher working ethics so you learn from them or at minimum they are not slowing you down.

iii) sharing the burden
People like co-founders because they feel it will be easier, that there will be someone to share burden of starting company with. Which may be true. However, if you skip above points than mostly co-founders are excuse and reason for a) not getting things done b) not taking responsibility and c) not making decisions. If you are by yourself, it’s all up to you. There is no-one to blame, but you. And because there is nobody else you are simply forced to do it.

Starting company by yourself is much harder than having co-founders. At the same time, you learn more, you experience more. It makes you much stronger and develops you as entrepreneur and person much faster.
At the end, also the reward is much higher.