disappointing a friend because of a relationship

the four of us are friends,
I, you and them both,
one time I had a relationship with one of us,
our friends that one man received with all things,
But you,
you are jealous and disappointed in me and him,
why?
not he be mine forever and forever not yours too ..
please understand this condition ..
you just smiled at me when I admit that,
but why now you sour to me?
you said I stab you from behind,

I do not think could happen like this,
forgive me friends,
i just wanted to get closer to him