This is totally an individual swan trait. He may be busy chasing the geese and thinks that this is his major role to keep them away from his family. In the meantime, he is leaving the child raising to the female. We have seen this in male swans before, but usually they stay in the immediate vicinity and will come rushing back to the family should they alert him to an imminent danger.

We also have heard about male swans which have one primary mate and then one on the side. Are you sure he is not stepping out on the Mrs.?

As long as he is still alive and in the area, we would not worry too much about this situation as he should eventually return to the family. The Regal Swan