Life had been nothing but a sore for you and Regulus since he met you.
He quite loved finally having someone that understood him, but Regulus ran from the first sign of love. It’s all he ever knew, and he had to make everything so complicated with the way he’d push away, turn into Mr. Misery and wallow in his sorrows, then crawl back like nothing happened — acting like his old self, sometimes even acting all chirpy as if he knew he wasn’t fooling you for crap. The one person that saw through him turned out to be a nuisance to him because of that.
Then, like life had finally decided to love him and take him into its nurturing arms that he had awaited for so long, he made some other friends. Okay, sure, they were all evil, or maybe they had a huge red target on their back from Tom and his posse, but they, too, understood him, and even if they were sometimes completely different from him, he’d adapt to their ways and change.
He changed for the worst. He faked every little thing he swore he had in common with them to fit in, did things he never thought he’d ever do, let his grades drop just so he could hang out won’t them, and started ignoring you, the one that saw through it all and tried to fish him back to you. You liked him the way he was, but he became somebody else, and he just looked like a straight up fool in your eyes. You’d laugh at the new outfits he wore, the new phrases he’d say, and he would flee like he always did. Like he always did.
Regulus was fooling everyone else but you, and he couldn’t stand that.