Urgent - Really need help from an experienced German Shepard dog owner

I'm not even sure where would be appropriate to post this, but I really need some advice from someone who has/had a lot of experience with GSDs. We got our almost 3 year old gsd when he was 8 weeks old and brought him into our home with our 3 year old lab and 10 year old lab mix. As a puppy he's shown signs of aggression with his food and some jealousy when we're spending time with the other dogs. Lately he's showing more signs of aggression toward our lab, they've been fighting a lot. Almost to where it's very difficult for my husband of almost 210 to break them apart and I can honestly say our gsd is the reasoning behind it. Tonight they got into the worst fight we have ever seen, our gsd would not let go of our lab while my husband was in between them, it was awful. Our lab just came up to me and my husband and our gsd went after her! My husband is at his wits end with it and very scared he's going to snap at our 15 month old daughter or us. I really don't want to get rid of him, my husband is very serious about finding him a new home but I really don't want to give up on him. Hes part of our family. He's never shown signs of aggression toward any of us, ever. Just a lot of fighting with our younger lab. We took him to obedience classes when he was a lot younger to teach basic commands, but unfortunately with our second child on the way and with us just having bought a new home, paying for additional training will be really tight with us. Does anyone have any advice to give me? Please help 😕