<human>: Older messages (while we were together) show that they actually met up when she was home for christmas and she said things like 'everything about us felt stronger than everything else' and 'I accept that I will never get you out of my life'. 

Those last two were both about 3 months into our relationship. I know they dated twice for a few years and they've known each other since they were kids but I also know he cheated and was an asshole to her. 

However she also has stated before that 'until me' she was the love of her life but now I don't even know if I believe her. She has promised me before that she had banned communication between them but said she would 'feel too bad' to block him. It is making me feel like I'm merely a stop-gap before they are finally reunited (for the third time too). 

Doesn't help that I come from a different part of the world and have no idea what they went through growing up together.How concerned should I be and is it worth approaching her or should I just pretend I never saw it?

Could you distill the essence of the text into 1-3 sentences?
<bot>: Found girlfriends messages to her ex which suggest she still has feelings for him, looking for advice on how I should react.