How to get my gf to cuck me?

I’ve had a cuckolding kink for around 5 years, and I really want to explore it more (especially being humiliated/emasculated).

We’re both 23.

Been together a little over a year, but sex life has gotten really dull past few months. Wasn’t exactly great before, I’ve never made her cum by myself (she’s always had to use a vibrator). She’s told me she’s been disappointed after sex before, and she’s also told me that she feels like she wears the pants in the relationship. I argued back but she stood on it.

She’s the second woman I’ve slept with, but I know she was with at least 20 guys before me. She’s also way out of my league.

I honestly have no idea how to bring it up, any advice?