Advice on a complicated relationship??

Okay so I have this extremely close best friend of mine (he's a guy and I'm a girl) and he's honestly such a sweetheart to me. Like if I have my period he'll get me a hot water bottle and give me cuddles and massages. We've been friends since the start of the year but around a month ago he kissed me? And we still kiss and make out now with some sexual elements (blowjobs and eating me out) but last week we tried (somehow) to have anal? And we done it maybe like 5 times after that? I don't really know what to do because yeah I enjoy this (don't worry it is consensual and he always makes sure I'm comfortable and okay afterwards) but it's like??? He always says "man, were like the closest best friends" or something along those lines. What should I do? (Sorry if this was extremely long and painful to read 😅)