As-Salaam `Alaikum sister,
You appear to be going through hell in your relationship. Your husband has behaved in ways that have caused you psychological and emotional distress, which is probably the reason you now feel repulsed from him. Feelings cannot be switched on and off when and whenever we wish. You are entitled to the way you feel.
It may be your responsibility to make the marriage work and try to create harmony within your household, but the responsibility is not yours alone. If your husband is telling you the marriage is over, and he is only there because of your son, then he is not entitled to having sexual relations with you because he does not come to you with the respect he should give to a wife.
It is not helpful for you to berate yourself and torture yourself about being sinful for not wanting to have sex with him or for wanting a divorce because you have to think what is best for both you and your children as it is also your Islamic duty to protect them. Ultimately, divorce and marital breakdown is abhorrent to Allah (swt) and society, but in conditions where you and your children are suffering from emotional and physical abuse, you have to make firm and strong decisions about what is important. Your children may grow up with longstanding emotional problems because they had to witness the type of abuse you describe. In such circumstances, your priority lies with their welfare and not what people may think of you.
Ultimately, Allah (swt) knows what is in your heart, and you should ask him for guidance and not punish yourself for wanting to escape the mental torture you are suffering.
May Allah (swt) help you,
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