My T wants me in DBT too. I was 100% resistant to the idea. She finally came up with an analogy to help me understand.

1. It's not "group therapy". It's a therapeutic class with a small group of people.
2. How is learning new skills a negative thing?
3. The analogy:
When you see your primary doctor, s/he treats your general physical health needs. But, if you have a condition that requires a specialist (endocrinologist, orthopedic surgeon, etc.), your primary doctor is going to refer you to one.
My T is in a sense my primary doctor (psychological-wise). If she feels that I need a specialist to help me with an issue, she's going to refer me (DBT). But she's still my T.

And here's a thought: if your future goal is marriage, the more effort you put into bettering yourself now, the better partner you're going to be to the one you love