I fall within the guidelines of this same problem. I just go. This is what I have to say about it. If you make someone pick between "who" they love and "what" they love, you probably aren't going to like their choice. So be prepared when you back someone into a corner. Loving a person, is about loving them completely. Even if you are a little taken back by their choice of hobby and other interests, besides yourself.
It is fair to offer the boyfriend to go along, if he chooses not to...too bad, for him. We get one ticket to live our lives and nobody should pass up the chance, to dance. If "spending time" with her, is important to him than he should make an effort to enjoy being with her, when she would like to do something that she enjoys.
Here is a little something I put together. She is more than welcome to use it. Perhaps, as a greeting card.
Hunting vs. Relationships, by Bethe Gettle
"My... huntin' and fishin', is important to me.
And, if you don't like it, you can get rid of me.
Just itch me off, just like you got fleas.
Cause, I'm out that door as soon as you leave.
Either sittin' on a bank or climbing up a tree.
You know darn well, what it means to me.
So you can sit here and cry, wonder why.
It don't matter, I'll hunt, until I die."
Thank you...thank you!