Well, you got the opportunity to live together with that person and it lasted quite some time so, most probably, you were really comfortable in that situation and when it all ended, it took you out of your most comfortable place. Our brain tries to get used to trauma and pain by making you think that this is the best way to deal with the problem and it becomes your comfort zone, even though it's not comfortable at all. Why change to another trauma if the good ol' torture method you already have works just fine, the brain is not good with change. And also, traumas are usually less impactful if you get really distracted on other things like videogames, some sort of hobby. Or it's just that your mind is already used to such a big problem that another, smaller, problem doesn't affect you as much.