Little question

Okay so I need to rant cause lord knows you can't tell a guy a fucking thing. My ex, who is still my friend because we just didn't work out but did not wrong to each other, reached out to me because he's super depressed and has no one else to talk to or listen. My boyfriend just can't get over the fact that he's my ex, and we're not even trying to get back together. He just needed someone to be there in a dark spot in his life and I help people, it's what I do best. I believe as long as you're not trying to cheat on your S/O there's nothing wrong with being friends with your ex. Ugh I'm just so stressed and idk what to do.