If the debt was his before the marriage, you may be able to negotiate out of it. Also, if the debt was during the marriage, it depends on what the debt is for - was it for his sole pleasure or was it for necessity to help the family. Those things are all considered when deciding who gets what portion.
As to child support, if is based on guidelines and who has the children the greater portion of the time and net income.
Net income is calculated by subtracting only 5 items from the parent's gross income which includes commissions, overtime pay, tips, bonuses, interest, dividends, rental income, royalty income, trust income, retirement income, disability income, etc.
Those items to be deducted are social security taxes, federal income tax, state income tax union dues, and health insurance premiums for the children. The proper applicable percentage is calculated by determining how many children the paying parent has an obligation to support.
You should consider consulting with a local Texas attorney, of course, before signing or agreeing to anything.
If you have further questions, you may post them here and i will continue to assist. Otherwise, even if you have a subscription with JA please remember to ACCEPT my answer as that is the only way I can get credit for my time and information in this matter. Thank you and good luck