Greetings Kilowat,
I’ve sent you a friend request via Battle.Net as I think you and your girlfriend would fit well in our guild, The Twilight Tier (Horde, Saurfang).
Our guild’s been searching for new members to get our active numbers up again, and we’ve recently begun Mythic+ dungeons as a guild group. We try to run a few dungeons a couple of nights a week, and we’ve managed to clear a +13 and are looking to see how much further we can go. That being said, we aren’t concerned about rushing things, we’re all here for a good time after all.
Beyond that, our guild is rather laid back with friendly and mature members. We enjoy chatting amongst ourselves mostly, both in-game and via the guild’s Discord server. We’re all anxious to get started with Shadowlands and see how we fare against the new content’s Mythic dungeons.
As much as we’d like to try raiding, it’s not our focus currently. If we manage to get enough members willing to go for 10-mans, we’ll definitely look more into seeing what’s possible.
Hopefully, we can talk more via PM’s. I’m looking forward to chatting with you. Regardless, best of luck in finding a guild you guys can call home 
~Veletala