The standard in Texas is going to be what is in the best interest of the children. If there is some Aston that joint custody is not in their best interest, then it is possible for you to be awarded sole custody. It is best to consult with a family law attorney to get a more detailed answer based on the specifics of your case.
There is no guideline based on the sex of the parent (mom v. Dad) but if one parent behaves in a way that could threaten the safety or welfare of the children, that parent is less likely to be gain primary. It is all about the Best Interest of the Children, not what parents want. Please consult a Family attorney in your local area. Many attorneys, like myself, give a free initial consult and can give you clearer guidance based on all the specific facts of your case. Take all documentation with you for review by any attorney you contact, you will get a better assessment of your possible options and outcomes
This answer is general information which does not establish any attorney-client relationship between the person asking a question and the person answering, or a duty to respond to ongoing questions; nor is it intended to replace competent legal assistance in the jurisdiction where the matter/issue arises or is before a Court.