I'd like to join Sophie_M in welcoming you here. Sophie gives good advice so I'm glad you met her already.
You sound like a most loving and generous person with a great deal of empathy and patience. Putting up with his ex, leaving your job, giving up some chances of having your own children and loving his are character traits any sensible person would appreciate and value you highly for.
The sort of abuse you have experienced is terrible for you and even would have had a bad effect on the kids. Sadly when in this situation self worth and self confidence are worn away until one doubts one can do anything. It's not true though, you can -and even be happy again (no, I would not beleive that either at this point, but it is true).
Heart-break and fear together can make the world seem hopeless and lets one forget there are good people and circumstances in the world.
Yes, you have invested a lot, emotionally and physically in this relationship, so it is easy to understand why you might feel overwhelmed at the idea of picking up the shattered pieces of you life and coping.
Can I suggest -if you have not already done so - contacting 1800RESPECT - 1800 737 732 - and talking over realistically what your options are. Things are not easy. Perhaps apart from practical advice they can lend some perspective.
Do you mind if I ask if you are having medical support to help with all the stress at the moment? Also do you have anyone in your family or a friend you can be with, talk frankly with and feel cared for?
Please know you can sing out here anytime about anything and you'll be welcomed