My girlfriend (F21) recently followed back her ex on Instagram, we've been dating for a little more than a year rn?

My girlfriend and I have been dating a little more than a year rn. She had her birthday recently and is also when i noticed that her ex has followed her and liked every picture of her and my girlfriend has followed back him as well

She didn't like her pics tho

I spoke to my girlfriend about this and she told me not to worry about it and said that "he just wished me for my birthday"

My girlfriend and her ex broke up about 4 years ago for additional context

I wasn't fully convinced

I wholeheartedly trust my girlfriend but i don't trust her ex and his intentions to reconnect with my girl after years!

I'm confused about what to do

My girlfriend (F21) recently followed back her ex on Instagram, we've been dating for a little more than a year rn?
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