Ex threatening to sue

My ex and I shared an apartment for a little over a year. The original lease was active from June 1, 2013 to June 30, 2014, and we started a new lease in July. I moved out on July 26th with very little notice, but I have paid half of rent every month since and paid the gas and electric bills for July.

When we moved in I paid the deposit and the first month's rent, and then paid at least half of all expenses until October when she quit her job. I paid for everything after that through the beginning of July of this year when I switched to a lower paying part-time job. If I remember correctly August's rent was paid out of her checking account, and I gave her cash to cover my half, but I can't seem to find any records that would back that up. From my online banking account I was able to download copies of all the checks written from my account since February of this year showing rent and the water bill that we pay to the leasing office paid in full from my account as well as quite a few checks written directly to my ex, but I couldn't get anything earlier.

My ex and I had a conversation over text in August in which I agreed to pay my half of rent due on September 5th, but she probably wouldn't need help after that. I told her if she did need help to let me know and I would pay as much as I could. That was the last I heard from her about money until yesterday (September 21st) when she told me that she would need my half in time to pay rent next week. When I told her that I wouldn't be able to come up with the money on such short notice she threatened to take me to court. I thought I was able to talk her out of that, but she told me today that I would have to pay rent in full next month if I did not give her half this month. My phone automatically backs up all my texts to my email, so I have a copy of all these conversations saved.

While we were still dating we agreed that she would cover the majority of the bills after I switched jobs, but we broke up a few weeks after I quit my old job and she told me that she was no longer willing to help with my half of the expenses. I really can't afford to continue paying half of rent on the apartment on top of my current living expenses.

What are my legal options in this situation? If she does take me to court will the financial records I have help my case? Is there a way I could remove myself from the lease? I would like to avoid going to court if only to save the hassle, but it seems inevitable if I don't keep paying her. It seems to me that the money she owes me should cover or at least come close to my half of rent through the end of this lease, but will a judge agree if this does go to court?

You can see if the property owner will remove you.
That's the only way to get off of the lease.

If she sues you, you simply defend.
But, she can't sue you until the rent hasn't been paid each month.

Now, the good news.
You don't owe her a dime.
Your deal wasn't with her, it's with the landlord.
Landlords will often agree for tenants to buy themselves off of leases.

Legally, the landlord is owed the money, your "ex" is owed nothing.
When you say "ex" do you mean spouse or girlfriend?
Not really gonna change much, just that a spouse would have more trouble suing you.
So, stop communicating with her, let her sue you.
Don't say you don't owner her, let her hear that in court.

As to any proof you paid her, well that's useless.
You don't know if she paid the landlord.

Just stop jaw jacking with her, and wait.
If you feel compelled to pay, pay the landlord ONLY - always get a receipt.

Thank you very much! I will contact the office and see if they are willing to get me off the lease.