A Switch dating and Dominating a Sub... and starting to feel a little bored

Backstory:

I love my boyfriend. We're both guys, both in our early 20's and both in love. I was always interested in kink and bdsm but never had a relationship to practice it in. He had never been with a guy and never felt comfortable enough with anyone to be submissive or kinky. I took the reigns and it's been going well since.

Before dating him, I'd had a few flings and short-lived relationships. Both men and women, and both topping and bottoming. Dominating and being submissive (especially this one domme who was a longer term fwb). And I enjoyed it all. But when I started dating my bf I took on a solely dominant role. I didn't mind it, not at the time, and I still really enjoy it. Honestly I'm pretty good at it I think. But... it's been five months being the dom.

I like being in control. But I also like giving up that control as well. Submitting. Letting someone else handle the hard parts and just following and pleasing. God I just want to please someone and be looking up, not down.

I plan on bringing at least some of this up to him soon. But I don't know how to bring it up, what to even say. And what's more, I'm not sure how we'd even fix this issue. He's really fit himself into the submissive mindset and bringing in a third person is really unlikely.

What can I do? How can I say any of this in a way that doesn't shake our relationship to the point of breaking?