Welcome! It's great to have you.
Birds go through stages just like people do. It could be he's now in his wanting-to-breed stage and you are an intruder into his relationship. He wants to drive you away. They call birds having a "pecking order" for a reason. He's showing you who is boss.
I would give everyone time to get used to each other. Just hang out with them as you are. Keep showing them that you're a part of the flock. But pairs do bond and it can very well be that they will bond with each other, as birds do.
If anything, I'd be more concerned about having a male and female together without being ready for breeding. Birds do do what birds are meant to do, and in this case it means have sex and make babies. So I'd start studying up on that!