The pair reportedly began dating in August last year, and went public with their relationship in October.
"I don't talk about my personal life much. That's why it's called 'personal life," Rousey told ESPN in a statement.
"It's true that Travis and I are in a relationship. I've really enjoyed the time we have spent together and getting to know one another. And that's all I'm going to say about it."
Neither couple appears to have made any official statement about the rumour.
Rousey will be the first MMA fighter ever to have the honour of hosting SNL and is just the third female athlete to do so in the shows 41-year history.
The appearance doubles as Rousey's first planned public gig since her loss to Holly Holm.
- nzherald.co.nz