My boyfriend is part of an online role play chat room – think he plays as a vampire or something. As part of this he has taken one of the other players to be his role play girlfriend (which I think is the main reason he goes on there but I don't know that for certain I could just be paranoid about it) is this technically cheating? Is it unreasonable to ask him to stop or should I just ask he not go on the website when he supposed to be spending time with me? We only see each other at weekends and we have already had lots of minor arguments about the amount of time he spends on there as I feel I'm being ignored.

Your going to have to talk to him about the boundaries of cheating, he may not think that having a fake online girlfriend is a big deal, but if you don't express that you don't like it then he won't know it's a big deal. Tell him what you really think of him playing on the site all the time rather then seeing you, and how its hurting your relationship because of it.

This isn't about cheating, it is about you feeling uncomfortable with his behavior and him needing to realize (after some open communication) that it bothers you. There are boundaries set up in relationships where expectations are laid out. If one of the two of you, or both of you cannot meet the expectations you know that the relationships isn't going to work. Bottom line, he has a real life girlfriend and that is what counts. If his actions don't encourage a healthy REAL relationship, then it is time to go.

The fact that you're uncomfortable with his behavior is already enough. He need to express your feelings clearly to him.

Like the others pointed out, you need to clearly state the boundaries and expectations of your relationship. Communication is key!

However, if he rather spend time with his fake girlfriend on the Internet, rather than his real girlfriend in real life, then it raises some red flags.