I think you just need to give it time and let them work it out. If you are interferring too much when he growls at her, it will make him not want to go near her.
As long as he is not snapping at her, I think they will work it out. Do not leave them together unsupervised until you trust that he will not hurt her.
Just try to be less involved in their interaction, and give each of them their own space to go to, to get away from the other one, such as a crate.
When you are holding both of them, if he growls at her give him a warning and if he does it again put him down. Keep repeating this until he gets the message.
Congratulations and good luck. |