I agree with most of what the other moms have said. A few different ideas; try to get into a mother of multiples group for socialization for you and your twins, and make some friends there. See what resources your college has; even most community colleges have a full time counselor and a student health center. If your college is entirely online, that leaves you a little more isolated, but there may be resources there as well. I teach at a Dallas area college and if you want to message me and let me know what college you're attending, I can find out some resources for you. Also I know that social work and counseling professors are sometimes approached for assistance and have a huge book of resources for all sorts of situations.
I'd agree with what others have said about getting professional help. If you're not able/ready to do that yet, find some TV shows like Dr. Phil or Oprah reruns that you can watch while he's gone, and/or get some self-help books. If you can't talk to a professional, at least maybe you can see others in the same boat and hear what professionals have said to them (and to the husband).
Your local college or Planned Parenthood may be helpful resources to avoid getting pregnant yet another time, even if it must be done without your husband's knowledge, and there are alternatives such as an IUD or quarterly injections that would be easier to hide, if needed. You can also refuse sex if he will not allow birth control after the baby is born. If he won't "let" you say no, perhaps that will bring additional clarity to your situation. My body, my temple.
He can't realize that you stay by your own free will, because it's about his own insecurities and control issues, and not about you at all. His insecurities only grow, leading to his need to bury you deeper and control and isolate you more; this anxiety that he feeds will only need fed more.
Consider how you would feel and react if your parents had treated you this way. Now think about how your daughters will feel when, not if, he treats them this way. I understand that you love your man and want to stand by him, but your utmost obligation is to your children if it comes down to protecting them from abusively controlling behavior....as well as to yourself. Try to be your own best friend, especially when you are so isolated and feel like you don't have friends, and when you feel conflicted, think about what you would tell a best friend or sister or daughter if she were in this situation. No amount of being a loving, wonderful provider makes up for this level of control. I grew up with an abusively controlling mom and sure wish my dad had stood up for us more. I ran away when I was 15 and 16, and eventually wound up in foster care.
You say that you're not willing to leave; okay, think about what is your line in the sand. What behavior can you absolutely not put up with, for the sake of you and/or the kids? Because guys like this tend to clamp down more and more and erode away your confidence and self-esteem, and the wife just keeps putting up with more and more and starts to believe she can't leave and that the behavior is her fault. I personally would not put up with what you've described, but where is your line and what is necessary for your health and sanity (and that of your kids), and what can and will you do if he crosses that point? That's where that exit strategy and emergency bag come in.
You sound like you are beginning to understand and assert your need for healthy boundaries, and like you're beginning to use more of your own critical thinking skills. Bravo for you! Continue to reach out to others for support and friendship, and think for yourself--and for your daughters. You are strong enough and smart enough to get through this, one way or another. There is hope for you. There is hope for your marriage if he will commit to change and counseling, and admit his problem, as others have said. Regardless, there is hope for you and your children, although the way may not always be clear or easy. You can do it, as many other have. Big hug!