Confused

I have a boyfriend and we will be going on a year soon. I know that he has a first love because they just graduated high school together and I will be graduating next year. However, he's in a different state than me temporarily because that's where he's from so when he graduated on Thursday and I saw a picture of him and her together and she commented "my first love" with a heart emoji. I literally semi cried myself to sleep because I feel that no matter how much I do or what I do she always has some way back into his life and I feel that she does it for attention you know? Prior to this way long before that she texted him and said she's still in love with him but he said I have a girlfriend that I love a lot so I'm confused and don't know what I should do because this needs to be cleared up. I get that we all have first loves but they have that title for a reason and to make it worse she has a boyfriend/girlfriend which ever one that is protective.