Looking for a manga...

Hi everyone! This is gonna sound complicated, but I remember only some stuff :-D Anyway, I'm looking for a yaoi manga I've read some time ago, it was about three guys having a crush on each other, two of them ended together, one of them was cheating - he tricked the third guy into sex by saying it's like he was making out with his crush (the second guy from the couple) and they ended up together...plus in the end they got tattoos, first letters of their names, so I kinda remembered they started with S and T, but that's all :( Anyone able to help me? :-D Thanks sooo much ヾ(☆▽☆)