Legal Question in Family Law in Texas

Assuming that there are no court orders in existence at all affecting the custody of your kids, and that no divorce or SAPCR petition has yet been filed by either party, then no, it would not be illegal for your to take the kids and move out of state. There is also a domestic violence defense to some of that if there is an order in effect, but I'd be uncomfortable relying on that except in a true emergency. The problem you're likely to run into is that you will not be able to file for divorce in Seattle until you've lived there for six months (the court your file in wouldn't have jurisdiction until then), and during those six months, your husband would have every bit as much right to come get the kids and take them back as you do now to take them without his consent. Depending on just how abusive he is, and what evidence you can produce of that, you might be able to qualify for a protective order to help keep him away from you and the kids, though, and it's possible that Washington has some other legal mechanism in place that could help you. You might consider consulting both a local attorney and one in Seattle to see what your options are. They might, for example, suggest that it could potentially end up working better to go ahead and file for divorce now in Texas, get a protective order issued here, then ask the court's permission regarding the move to Seattle, with the agreement that you'll come back whenever needed to deal with hearings, mediation, etc. on the other hand, as I said, Washington might have some wonderful way of dealing with this situation that we've never heard of that might be better than what you could do down here. Good luck--I hope things improve for you soon.

Actually, here's one more thing to think about. I just noticed you say you've been married for ten years. I don't know what your financial situation is, or how important that end of things is to you right now, but if you've gotten to the ten year point, you at least potentially qualify for spousal support payments if you'd otherwise be unable to meet your basic living expenses. I have absolutely no idea what your situation would be if you moved to Seattle and filed there, but be aware that your filing decision could also affect the financial end of your divorce.