Well,... It looks like the initial spell of the relationship has waned, and you are confronted your first crisis (if your relationship survives this, there will be many others).

Basically your relationship needs to grow, or it will die. It can't afford to stay the same as in the beginning. So I suggest that you find more common ground than just Metal Gear, and diversify the kind of things you do together. Organize stuff together, create some shared memories, get to know each other better. It's a bit too soon to feel you know each other too well.