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There is a presumption that all property possessed by either spouse is community property. Separate property ownership must be proven by clear and convincing evidence. In Texas, the appreciation or increase in value of separate property is generally considered separate property. However, reimbursement may be due to one spouse or the community for contributions made during the marriage to enhance the value of one spouse's separate estate. (Reimbursement can work the other way also--separate property used to enhance the community property).
So basically though the house was purchased prior to marriage, the fact that you contributed to the payments does give you a legal interest in the property although it would not be a large interest.
You would have to contact the local attorney bar association to find a listing of attorneys who will offer free or reduced rate divorce services to assist you.