I am not an accountant or attorney. NOTHING I post should be see as direct tax or legal advice. This answer is solely based upon my personal experience.
I own/operate a single member LLC in the US.
The key word in LLC is Liability, As a US based, single-member, LLC there's not a great deal of tax benefits. You can still file individually and it doesn't change the tax rates. Now, I'm not married so there may be further considerations due to that which I'm unaware of. Only an accountant could answer that effectively.
The only reason to use an LLC if it's a single-member LLC is to protect personal assets against business claims. Even with that in mind how you manage the personal and LLC finances plays a large role -- the need for separate bank accounts, tracking how you spend any money from the LLC account, tracking how and when you take dividends from the LLC. If you fail to manage money correctly, it's my understanding that a single member LLC can easily be dissolved by a judge should an issue arise.
In my personal opinion, if there's no worry about legal claims against the business, there's no need for a single-member LLC. A sole-proprietorship will offer pretty much the same tax status and merely removes any liability protection.
Again, I am not an accountant or attorney. Nothing in this answer should be seen as legal advice.