Thank you for contacting JustAnswer.
I am sorry to hear about the problems you are experiencing. It is extremely difficult to be in an abusive relationship, particularly because things are never all bad or all good. Your husband may at times act in ways that are not abusive, making it difficult to tell when he may revert to abusive behavior, and perhaps making you think that things may get better or that you should stay. Abuse is often about controlling the other person. It is understandable that you would react with anger to this type of treatment. I am glad to hear that you have been using your faith and support system to help you through this. You may want to consider individual therapy as well in order to get some support for yourself, build up your self esteem, help you to set boundaries, and work on deciding what is best for you. Remember that no one deserves to be abused. You may find the following website helpful: http://www.mentalhelp.net/poc/center_index.php?id=2
In the meantime, be sure to take care of yourself through healthy eating, exercise, rest and reaching out to supportive people in your life. As you have discovered, affairs are not helpful as they typically only serve to complicate matters further. They are generally only a symptom of the problem.
One thing I would add is that it seems that you have been doing quite a bit of emotional work about this relationship. In order for this to be a healthy relationship, we would expect your partner to do a relatively equal amount of emotional work (if you balance it out over time). This may be one way to evaluate if someone is committed to a relationship and to changing in order to make the relationship work. You deserve someone who will put the work into the relationship as well, since it takes two people to make it work. Also, I definitely believe in trusting your gut. It is often a very good indicator of red flags that should not be ignored. Feelings of love tend to be very irrational, while the gut is a good barometer of danger, both physical and emotional. I hope this answer is helpful. Please let me know if I can clarify further.