Depression , feeling guilty. Advise.

Hello, From your statement it looks like your life is in chaotic situation at present. You have mentioned that you had an affair with a married woman and who has a kid too, now as  both the families got to know about it and  you are feeling guilty about the same and you are holding your self responsible for what is happening in your girlfriend's family. Trust is foundation of any relationship especially marriage if that is broken down then the relationship lose it's meaning. Give some time  to both partners; your wife and to your girlfriend's husband, do not interfere in their personal space. Let husband and wife decide how to go about with their relationship. Here I would want you to ask yourself few questions Why did you enter into a relationship outside your marriage? Why did your wife get back to you despite knowing about your infedility? Here on can I make my relationship with my wife strong? Was your relationship with your girlfriend mutual? If so then how are you responsible for what is happening in her family?

Always remember relationship is about two people and both are equally responsible for what is. you can blame yourself for that.

consult a family therapist to strengthen your relationship and seek individual therapy to deal with your guilt.