Obviously, a writer writes because they want people to read their work. But this early in the process, you may not feel comfortable letting just anyone read it – you are looking for honest feedback on the quality of the work, so you can improve it before it is published. It’s a time when most (perhaps all) writers are at their most vulnerable. They have given birth to this part of them and recorded it on paper and no one wants to hear that their baby is ugly.
It’s important to put some thought into who you ask to be a “beta-reader.” First, it should not be a large number of people; probably no more than five. Second, it needs to be people you know you can trust. That doesn’t necessarily mean close friends. It might just be an acquaintance who likes to read. You could potentially receive the most honest feedback from a person like that – they might tell you things that your friends won’t, because your friends don’t want to hurt your feelings or crush your dreams of becoming a world famous author. Be prepared to hear that your baby is indeed ugly, however.
Other writers are also a good source of beta-readers. If you don’t know any writers, it’s time to find some! Join a writers guild, or attend a writers conference and network a little. Find one or two that you click with, and exchange contact information. There will come a time when they need a beta-reader too – it’s a mutually beneficial relationship.
Lastly, unless your spouse or significant other is an avid reader, I wouldn’t recommend you seek their feedback. They are going to love your baby no matter what.