I would say to get your head straight first and then "be there" for your family. If you are hurting them, then is it good for you to be around them? You need to get help for yourself so that you can be the parent you want to be. I think you should be totally honest with them and let them know you are starting therapy. That way they will understand that it's not their fault, it's just that you need help right now. Love yourself and them enough to get well. Big hug!!