He loves Juliet.
Juliet: "Romeo, Romeo, Wherefore art thou Romeo?"
They died.
The Friar advised Romeo to be cautious in love. He reminded Romeo of the love had for Rosaline and the haste with which he abandoned that love.
Rosaline. The last they heard, she was the one Romeo was after.
In his speech, Mercutio thinks that Romeo is in love with Rosaline, a character who is unattainable and does not return Romeo's affections. He addresses Romeo's infatuation with humor and sarcasm, highlighting Romeo's romanticized and idealized view of love.
Juliet, of course.
When we first meet the friar, Romeo is coming to tell him about his love for Julilet and how he wants to marry her. The last the friar heard, Romeo was in love with Rosaline.
Romeo and Juliet's problem is that they are in love but their parents don't want them to marry or stay together.
romeo confeses to benvolio that he is in love.
Rosaline
romeo and Juliet
In Act 1 Romeo tells Benvolio that he is in love but his love is not reciprocating.