I’m an over analyzer, so if I did any minuscule thing to make him think I was interested romantically, I would remember. I also think about how he would interpret our conversations/intersections and lack thereof. I can’t think of anything that would be a glaring “I like you” sign to him.
That heart text was intended to be friendly, and any logical person would assume that, especially in context.
I’d like to think that he said it to protect his ego, if he believed that I don’t see him as more than a friend, he would preemptively cut me off before I could verbally reject him. That’s still plausible, right?