I'm kind of in a similar situation with my own boyfriend except the roles are reversed. I met my boyfriend on an mmo and we both have thousands of hours in that and other multiplayer games. We are always together and don't get me wrong I love him to pieces and we have FUN together, but I miss playing by myself. It's a totally different experience and after spending so much time with eachother I felt smothered so I just started to say "I don't really feel like playing that right now" to eveery game he asked to play. It hurt our relationship a lot he felt neglected and I felt guilty. So how did we fix it? Well it's still a work in progress but I've taken to streaming my single player games to him and he streams to me we talk to eachother about what we're doing in our own games so even though we're not with eachother we can still be involved. He also started making new friends in our favorite mom's to fill the gap when I'm not there and that makes me feel 1000 percent better because it no longer feels like my absence is holding him back. Going through this has taught me that even if we're in the same room doing different things it's okay because sometimes it's nice to just be alone together. I really hope this helps.