<human>: Could you distill the essence of the text into 1-3 sentences?

So here's the story, names changed for privacy. I live with a couple, Evan [the 22m] and Aria [22f]. Aria's friend Michael [30m] recently moved in with us. Michael is not only Aria's friend, but also her ex-boyfriend. It's been 2 years since they dated, they've been friends in the meantime, and Evan was cool with it, so I was also fine with him moving in. 

It is very obvious to me based on body language, and actions Michael does towards Aria that he is still totally not over it, and likely still in love with her, even. He makes food for her, rides the bus to her work (about an hour bus ride each way) for the sole purpose of riding the bus back with her, and as much as possible when Evan isn't around, he positions himself as close to her as he can. It's painfully obvious to me and Aria doesn't do anything to try to brush it off. She's a very attractive girl, and I think she thinks of actions like this from men to just be commonplace and almost expected. I am 99% sure that she would ever cheat on Evan, but it seems to me that the possibility of Michael making a drunken move on her when Evan isn't around is definitely likely, in which case he would probably need to move out of the house and the remaining housemates would have to eat the cost of his rent.   

Should I talk to Aria about it? Or Michael? Or is it really none of my business?
<bot>: My male housemate who is my female housemate's ex boyfriend is clearly digging on her too much when her current boyfriend who also lives with us isn't around. Should I say something about it?