Married 17 years. Together for almost 21 years. 3 kids
That's not enough information on which to answer. You need to analyze what you have - so consult a local attorney and discuss the situation in detail.
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Divorce / Separation Lawyer
In order to provide a realistic answer to your question, more information is needed. I recommend contacting a divorce attorney in your area for a consultation. Good luck.
Family Law Attorney
It depends on alot of facts not stated. On Child Support, it depends who is the custodial parent and how much time the non0custodial parent spends with the minor children and how much money is earned by both parties. Concerning spousal support, generally for a marriage of this length, the court has alot of discretion on spousal support and it depends on 14 factors in Family Code Section 4320. Please seek help form an attorney on these matters.