Why is my boyfriend only adding ladies on social media?

I recently found a dunkin Donuts receipt in his car for 2 woman at work. He swear he picked up their food but I have my doubts. There was trash on the floor of his car from dunkin. Also it seems he's just getting to friendly with female staff, there is a new girl who he keeps mentioning frequently... We been together almost 3 years but my trust in him is not great because he keeps hiding stuff. He said this new girl asked to add him on facebook incase she needs to get into work and the door is locked. Like call the job but no we gotta add each other on facebook... Also he never adds any males from work. So im unsure of how much I can trust him. Any advice is appreciated.

Why is my boyfriend only adding ladies on social media?
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