So Vincent, where are you ? are you saying ths is happening here in UK ? if so, stop messing about with her, and sort it.
Go to the house yourself, find out who this Alex is, and feel his collar, is he Filipino ? if so, warn him off, ensure he realizes just how intensive care has deterioated these days in UK.
Make it clear to your girlfriend that she is jeapoardizing your relationship, I would not worry about Ben Afleck and Brad Pitt, apart from the fact they are both taken, they are not your immediate problem, she is just jesting and having fun.
The Alex business however is more of a clear and present danger, you need to terminate that situation asap.
