I agree with <3 - you can't say that you love your boyfriend and be annoyed about him thinking about going on holiday without you, and then the next minute say that you are thinking about another guy loads.
I'm not sure that you are thinking about this the right way. If, as you said before, you are annoyed about your boyfriend going away wihtout you/without mentioning that he was thinking about it, then you are bound not to be in the best of moods with him. Ask yourself this - would you still be interested in Simon if your relationship wasn't going through a rockly patch at the moment?
I'd say work at your relationship, don't just give up on it as soon as someone else comes along, that's just not fair.