Hooked up w guy best friend, cheated on bf

I am in college and my bf lives in another city, he already graduated college and we see each other once every month or two. For a year we had no trouble keeping our LDR but now that I live in an apartment, I have more freedom and my guy best friend lives right across the hall from me. One time, I stayed over at his place and we ended up hooking up(we did not have sex tho). It only happened once and we're still friends even though he acts weird sometimes but I feel guilty bc of my bf and we barely even talk anymore, he knows this and gets mad at me. I tried to break up w him once but I couldnt do it, i love him too much even though i know i betrayed him.

What should i do??? 😭