As far as I know Australia wants young people! Because of your age you're definitely eligible for the Working Holiday Visa, if you haven't used it already. I think that the 10 months might not count if you're separated afterwards. My partner and I didn't apply after living together for 12 months cumulatively, only now that we've lived together for over 12 months without a break. Then again, we just assumed we wouldn't be eligible on the previous occasion. I guess you could always ask.