They ended up fighting all the time. Seems like this can happen a lot at the age of 7/8, as females become calmer but males stay active. She was annoyed by him. Didn't help that she became asthmatic, so she couldn't keep up in play fights at all (also because he's larger then her). Miez was stressed out all the time. I took in Lilly as a playmate for him, but then the both of them still stressed out Miez. Luckily I found a new home for Koda and Lilly with a friend's family. I know they are in good hands there and I visit them from time to time, as well as sit them during my mate's vacation (Miez then stays with my parents as she gets along with my mother's cat Franka). Check out my other posts for more pictures of all of them.
P.S. I see the downvote bot is still active around here.