I know this weight is probably really weighing heavy on you today especially having to go into work feeling so confused and guilty. I agree with you on raising your son around parents who are not fighting it can be really frightening I experienced it first hand and I wish my parents had divorced sooner because it was a never ending argument so maybe couples therapy could help you two get back on track if that is something you are interested in.
Just be gentle with yourself people make mistakes no one is perfect, try your very best to not let it happen again because it will only cause you more pain and further complicate things. I think a therapy session would help you get out your emotions and figure out what is best for your family. I wish you the best.