adding another ray won't stop this, my male did the same after their 2nd litter, I sepperated him and put him with another male his size and one even much larger than him and he bit the heck out of the 2 males too then about a month later he just stopped.
No documentation to back this up and going on my own observation and opinion, I think the male is excited about "getting some" and if the female is already prego or not at full health to concieve again she was refusing and he was determind and when he was with the large males he still would bite them and once he came to the realization he wasn't going to "get some" he calmed down.
Did you notice if he is eating less & more focused on trying to breed?
---As above, best suggestion is to sepperate them or a strong divider (aquamojo I believe sells dividers strong enough for rays---you can usually find him in the cichlid or photo forums)