I am in my late twenties and I have been dating him for over a year. I am not looking for someone to support, I got introduced to him because we work in the same field.

I'm a woman. I don't think it matters what anyone thinks. You are an adult, and not just a new adult either. I'm wondering why you are asking. Is your father disapproving?

Not saying I would be happy about it, but my greater concern would be whether he was a good person who would do right by my daughter. And also my daughter's feelings for him.

I wouldn't be happy, but would try to have an open mind about her choices.

What exactly is the age difference?

Assuming girl is in mid 20s or latter, it is her choice. I may not be happy, but she has to live her own life.