I signed a lease five months ago with my roommate (both names are on the lease), and after only a month, she started staying at her boyfriend's apartment 5-6 nights a week. After another two months of that, my fiance started staying at my apartment in my room. She is trying to say that because she is never there and he is, he needs to pay a third of the rent and he and i need to split utilities (not her though, even though she still uses the shower, toilet, sink etc the one or two days she comes home. I know it is just a jealousy issue because she is mad that my fiance and i are happy and content with each other.
She claims we are disrespectful to her (but how can we be when we hardly ever see her?) and that he LIVES here now. On the disrespect issue, my fiance has been nothing but nice to her since he started coming here. He offers her dinner if he's cooking and she is here, he offers to change the oil in her car, he even cleans at our apartment (which she has only done once in the last five months).
She brought up the fact that he gets mail here, but I told her it is because they are financial things, and I take care of it, which is true. We're trying to get things in order before we are married, and I am in charge of our finances.
I talked to my landlord because I am sure she will try and get away with only paying 1/3 of the rent, even though I already turned in a check for my half. My landlord gave me a few options. I can find a new roommate and she can move out (if she agrees, but she won't), or I can pay the rest of what she doesn't pay and take her to small claims court, or I can do nothing, and it will go to collections (in both of our names, of course).
I plan on going to the office today and asking if she has paid yet, and if she only paid a third I'm planning on paying the rest so there is no late fee. But I can only do this for this month and then I will have to borrow from my parents (I'm a broke college student). If I take her to court, will they see it her way?
I say, her name is on the lease, she and i are equally responsible for rent so she needs to pay her half. Can she say anything about him getting mail here and will that matter?
Any other advice or comments?

I can certainly understand this is a frustrating situation for you. I suggest you contact an attorney to determine your legal options. You can find an attorney through the locator service on LawInfo’s home page at: http://www.lawinfo.com/.

That said, sounds like you have a pretty nice landlord to explain all of that to you. According to most state laws, your landlord is probably right. Usually, both tenants are responsible for the rent... usually the roommates split it in some equitable way... but from the landlord's perspective, there is no separate rental agreement with you, and with her, its just one - so you could be left holding the bag if she doesn't pay. Your rememdy is to sue in small claims court. However, if she's never there, and doesn't want to pay, and doesn't want to be there - what makes you think she wouldn't want to be released from the lease? Maybe that would be a good solution and you can find another roommate. Or, perhpas your landlord would allow you to move into a different unit?

You might find some additional help with these resources:

http://www.hud.gov/local/ia/renting/tenantrights.cfm

See also, from the Iowa Bar Association: http://www.iowabar.org/Public%20Info...b!OpenDocument