Can my kids mother move my kids out of Texas without me knowing

If you bring a suit in the county where you and the children have been living prior to the move, and request that the mother be ordered to return the children to Texas, the court is likely to order that the children be returned.  You may want to request primary custody of the children.  It is a policy of the State of Texas that both parens should be involved in raising the children.  In the State's view, raising a child who lives in another part of the country or State is not as good as the situation where the parents and the children all reside in the same county or set of counties.  Do not delay in bringing suit, or you may lose some rights as the mother and children establish residence in the other state.