My husband was arrested in July 2016 for restraint and domestic assault. I called the police on him. Since then, I have stood by him. . . .
Other than you "stand[ing] by him," what has happened with this eight month old incident? You told us he was arrested. Has he since been charged? If so, has the case gone to trial?
Can someone give me an idea of what I can expect if I move forward with the divorce and how the courts would work?
This is an awfully broad question, and it is made even more broad because of the criminal issue and the lack of clear information about that issue. One thing that you need to understand is that, until the baby is born, you are free to go wherever you want. If you think you may want to return to Canada, you are probably far better off doing so ASAP than waiting. I don't know if Canada or its provinces have residency requirements for filing divorce (in the U.S., the various states impose residency requirements that vary from 30 days to six months). If you are able to establish residency in Canada, you can file divorce there. Of course, your husband can file divorce in Texas at any time. I strongly suggest you consult with a divorce lawyer in your home province about the residency issue, and you may also want to consult with a divorce lawyer in Texas.
My husband isn't a green card holder yet; he has an Indian passport and is on an OPT STEM work visa. He earns about 20K more than me, in case finances are considered in these things.
None of this will matter if he is deported as a result of the criminal matter.