I had two males. I got them as puppies. They were both fixed. They did pretty well for a couple of years. They would play and got along great. Then, some little thing would set them off and they would fight. Brutal fights. I would have to separate them to stop it, which wasn't easy since they were both around 80 pounds. I got hurt once, in the process. They tore my leg up pretty bad. I learned to not feed them close to each other. I stopped giving the bones because they would fight over them. I managed.
Then, when they were each about eight years old, I found that one of them became very territorial about me. If Baron came near me, Dodger would go for him. I was on edge all the time. To make it worse, my daughter was about six. I was afraid for her.
I ended up giving Dodger to a friend who wanted a dog, but didn't want to deal with a puppy. It worked out. Dodger lived the rest of his life with his new owner and was happy. Baron was fine with us.
I decided I would never again have two dogs of the same sex. I had a male and a female golden retriever. They got along fine.