Do I need an attorney to file a divorce?

You don't need an attorney for anything in a divorce if you understand the law and procedure required.  If you don't fully understand the law or procedure you can get run over, and WILL get run over if the other party has an attorney.  I suggest you pick up a copy of "How to Do Your Own Divorce In California" published by Nolo Press.  If, after reading it, you feel comfortable you know what to do and how to do it, you can join the thousands of Californians who get divorced without an attorney every year.  If you are worried you still just don't get it, or if you run into issues the book says you should get an attorney for, then you should at least consult with an attorney in person before proceeding and possibly getting into trouble.

There's no legal requirement for you to have an attorney, just because you're requesting spousal support, but it's a good idea, because the legal issues (and sometimes the facts, also) aren't simple.  The length of your marriage, and the earning capacity that each of you has and what you could have with some education or training, are just a few of the important factors that have to be considered.

"Gifted" items can be difficult proof problems.

Getting his part of the rent will probably require a temporary support motion, early in the divorce.  Again, this is something where a lawyer isn't absolutely required, but having one can make a very big difference in the result.