So my housemate who I've known for 5+ years (and has only had two girlfriends that I've seen so is very BP) has been dating a new girl for a few months now, however to me its like watching a train derailing in slow motion, I know this is bad for him but I also know he's very stubbon and might get funny with me if I pull him up on some of this stuff, so heres a few tidbits:

  • They have been dating for 3 months. Within 3 weeks of dating he had booked a holiday to New York for them both costing him around $5k
  • Her Ex-Bf bought her a rabbit when they were together but he kept it after they split up. Within 8 weeks of being with my housemate he had bought her a new rabbit and built a palace for it that he keeps in the back garden of our house
  • Whenever they go out somewhere he drives whilst she leaves her car at our house
  • She is round for dinner often which he cooks and I assume he pays for fully
  • Shes been to known to abuse drugs in the past, namely cocaine and MDMA
  • She is a known slut/cheater confirmed by multiple sources. She cheated on her ex-bf numerous time (one story I've heard about her BF finishing her off after the guy she was cheating with had to bail out of a window, BF was clueless of the cheating)
  • Me and my other housemate have suspicions that he may be thinking about buying a house with her or at least buying a house and having her move in (We saw him looking at mortgage rates last week)

Should I say something. Obviously its difficult for me because I live with the guy and I'm sure this is going to end up being a very bad relationship for him.

Tldr; Housemate dating a cheater/slut, housemate treating her like a princess, should I say something?