I am with a 50yo who also adores gaming.
His last-but-one partner left him because of it.
His last partner didn't, but they were completely indifferent with each other by the end because he was always gaming, and he ended up finishing with her.
He told me this when we got together. I said I didn't mind him playing games, so long as he pulled his weight in the house, came to bed at a decent time most nights, and spent at least some evenings together. Sometimes I will have some things I want to watch on TV that he's not keen on - so he'll go on then. Sometimes I will go to my parents' for the evening, and he'll game then.
It's about balance.
If he's online, and I'm feeling lonely, I'll give him a shout and he's ALWAYS downstairs within 10 minutes (but I don't take the piss, I'm fair, and respect that he has his hobbies just like I have mine).
Gaming all day on Christmas Day? That could fuck RIGHT off. This week is a week for family. He hasn't turned the computer on at all, and I doubt he will.
This has not been prompted by me. In fact, when we were wrapping presents I suggested he went on it as mine were better and he was more of a hindrance haha.. but the point is he wanted to spend time with me at this time of year, because that's a normal thing to do.
I would not be standing for his behaviour.