I will put my hands up and admit to being a person who has done this.
The problem with our relationship was my bf and i got to a point where we were in such a routine, he spent his evenings playing xbox games against his best mates and i sat on the laptop, i am only 20 myself, he is 25. When he was playing his games, i felt i couldnt talk to him or anything as he didnt like being interupted, so i went elsewhere to get attention, which i know was completely the wrong way to go about it! In the end i admitted it to him and he was very hurt and i will never forgive myself for making him feel that way. We spent a long time talking about us & things, and after that evening, he never played online xbox games again, as he felt he was to blame. We made a huge effort to sort things out, and things are absolutely fine between us now.