Help me guys!

I don't remember the name of this one yaoi but I do remember that the mc was like a teen or something and was in a relationship with someone older than him. He didn't have a home since he was kicked out I think so he lived with this older dude that may have gotten him into smoking. It's later revealed that the older dude was dating someone else who looked very similar to the mc. Please help me find it!! (/TДT)/ m(_ _)m