D., this is as clear cut a case of controlling and abusive behavior as I've ever seen. This isn't a healthy marriage. Please, you need to end this. I see that another response already included the domestic violence hotline. Call this from a safe phone and they will get you in touch with your local resources so that you can plan an escape plan. If you have a plan in place, you are more likely to successfully get out with your child(ren?) the first time and not end up going back to him because you're desperate, vulnerable, broke, afraid, etc.
Please be very careful with your computer. Learn to clean up the history so that he can't see things like this question. If at all possible, use a computer at the library to do this kind of correspondence. Set up a separate e-mail account that you never access from your phone or your home computer if you need to keep some e-mails from him.
I wish you strength and safety as you move forward. Please know that if he senses you are planning to leave, things could turn physically violent, so be careful and make your move as soon as you can.