If you and your spouse are not on good terms, then you have no choice but to file for divorce in Texas.
Texas does not have legal separation so a divorce needs to be filed.
If children or money (or lack of money) is an issue, you need to file for a divorce and ask for the judge to enter temporary orders while the divorce is pending.
A spouse cannot leave and abandon the other spouse and children.
But if you don't do anything then the judge cannot help you.
If you have no money, I suggest you borrow money from a family member or friend to hire an attorney. If one spouse controls all the money then the judge might order that spouse to pay the other spouse's attorney fees (or a portion of their other person's legal fees). However, it is up to the judge.
I'd use www.avvo.com for an attorney in your area. It's the best free site that I know of on the internet.
If you want to do it yourself without an attorney (good luck!) then use the free Texas forms at www.texaslawhelp.org - these forms are very basic and don't include retirement, real estate, brokerage accounts.
Please do NOT use a paid site - especially one out-of-state - I have seen their forms and they are laughable. Their guarantees are worthless.
If you have money, please hire an attorney and do it right. For example, in order to divide a retirement account, a specific legal document must be prepared to order the company handling the retirement money to do things to divide the account. A final decree of divorce is NOT enough. There is a legal document that ORDERS the company to act. Otherwise, without this legal paperwork you might be ordered to receive the money but if the other spouse spends it (hides it, gambles it away, etc.) then you are out of luck.
It is heart-breaking when a person calls years after the divorce has been finalized and they did not do the paperwork and now the money is gone.
There is often nothing that can be done at that point to recover the money. (If the person has other assets, then a lawsuit might be appropriate to recover the money but it won't be fast or inexpensive. Attorneys charge thousands to "fix" bad divorce paperwork.)
If you are totally alone and have no money then you can look on the State Bar of Texas website for a pro bono (free) organization in your county. Expect to wait for months for a free attorney. These pro bono groups are understaffed and underfunded. These pro bono groups do NOT accept everyone that calls them. They make you just through tons of hoops and then still don't get you an attorney.