Mercutio, apparently a haunted former soldier, could, perhaps be termed a "nihilist". His attitude towards love, therefore, is the same as his attitude towards just about everything else: it's all ultimately meaningless. Despite this, Mercutio has an immense appetite for life's simple pleasures (friendship, drink, wordplay, horseplay, swordplay), but he has killed for the state, has seen death, and he senses the futility of life and all its machinations (such as the ancient and pointless ongoing feud between two otherwise perfectly respectable families). Mercutio is given to us by Shakespeare as something of a foil for his friend, Romeo. Younger and still idealistic, Romeo does not live as recklessly as Mercutio, but, because of his aged cynicism, Mercutio would seem incapable of loving anybody with the same dedication as Romeo.
Find text to back this up yourself. Scan all of Mercutio's monologues and exchanges with Romeo. Look for the word "love" to begin with, but also take note of his fun-loving yet fatalistic approach to all things. Personally, I would begin with the "Queen Mab" monologue, beginning in Act 1, scene 4, line 53...
Love? Mercutio doesn't speak of love. He mostly taunts people.
Mercutio teases Romeo about his love sickness regarding Rosaline in Shakespeare's play "Romeo and Juliet." Mercutio mocks Romeo's infatuation with Rosaline and portrays love in a cynical and humorous light.
If love be blind, love cannot hit the mark.
Mercutio praises tybalt in an attempt to attract Romeos attention
He isn't in love with anybody. If you ask me I don't even think he believes in love
Romeo takes love seriously; Mercutio does not.
Mercutio accuses Romeo of being afflicted by love-sickness, specifically for Rosaline. He mocks Romeo for his infatuation, attributing his behavior to being love-struck.
Mercutio makes fun of Romeo after the party because he thinks Romeo is acting love-sick and overly dramatic about his feelings for a woman. Mercutio's teasing reflects his playful and sarcastic nature, as well as his skepticism towards romantic love.
Romeo is deeper than Mercutio. Romeo is more romantic then Mercutio who has negative feelings towards love. Mercutio is a realist while Romeo isn't. Mercutio is into fighting while Romeo wants to talk things out.
He jests at scars that never felt a wound.
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.
Mercutio interprets Romeo's actions as fickle and inconsistent. He sees Romeo's love for Rosaline as shallow and insincere, and believes that Romeo is being overly dramatic and moody. Mercutio tends to view love as a game and doesn't take Romeo's passionate emotions seriously.