Let me begin by saying that generally a lawyer is NOT appointed to represent a parent in contested custody action. For that reason, if you cannot afford to hire a lawyer, I am going to strongly urge you to apply with your local legal aid office as soon as possible for detailed advice and representation. Legal aid (sometimes referred to as legal services) represents people without their having to pay attorneys fees.
Without knowing all the particulars of your situation, it is impossible to say whether you should leave now. That is something that you will have to speak with your attorney about in a sit down consultation that will allow you to go into greater detail that we are able to do here. Another issue you will want to consider and discuss is whether you should apply to the court for permission to relocate in advance of your move. While it is possible that the court can order a relocating parent to return to the state, it is also possible for a relocating parent to get a temporary order allowing the relocation, pending final determination.
Whether you file first or whether he does, once the matter comes before the court, the judge will decide whether to allow the relocation by taking into consideration a number of different factors. The primary concern, though, will be whether the move will be a positive improvement for and in the best interest of the child
. TEX. FAM.CODE § 156.202(2)
Some factors that the court may consider include the motivation for your move, the economic benefit to the child (e.g. better job for you) and the academic benefit to the child (e.g. better schools for the child). In any relocation case, the court will consider how the move will affect the relationship between the child and the non-relocating parent, but also the existing relationship between the two and the role each parent has played in the child's care and upbringing. Unfortunately, there is no bright-line test available for me to give to you, as each case is decided on a case by case basis. What I can tell you is that the court will consider and balance numerous factors, and taking together any and everything having anything to do with the child's welfare decide whether it would be best for the child to go.