Romeo's male friendships with Benvolio and Mercutio become slightly strained, first when he becomes obsessed with Rosaline and then again when he falls in love with Juliet.
We see the first suggestion of strained friendship when Romeo refuses to confide in anyone about his misery. As we learn in the first scene, Romeo's father tries to get him to say what is troubling him and many other people as well, but Romeo continues to keep his misery a secret. Finally, Benvolio decides to give it a try. Romeo confides that he is in love and that she "in strong proof of chastity" has vowed to remain chaste and rejects Romeo's love (I.i.212-13). However, he refuses to tell Benvolio the name of whom he is in love with. By the second scene, we learn that Benvolio has guessed her to be Rosaline.
We see more signs of strained friendship when after the ball Romeo breaks away from Benvolio and Mercutio. Romeo jumps the orchard wall in hopes of another look at Juliet, but thinking that he is still obsessing over Rosaline, his friends believe he has run away from them so that he can be alone with his foul, lovelorn mood. However, his friends think that his behavior of wallowing in self-pity is wrong and are annoyed by Romeo's disappearance. Mercutio refers to Romeo's disappearance as a "false impression," meaning that he was a false friend, as we see in Mercutio's line, "You gave us the counterfeit fairly last night" (II.iv.45). However, neither Mercutio nor Benvolio take Romeo's poor behavior seriously and are willing to understand it is due to heartbreak. We see just how lightly they take Romeo's behavior when they continue laughing, joking, and being friendly with Romeo in this very same scene.
While Romeo's love for women may put a strain on his friendships, his behavior certainly does not put an end to his friendships. Because his friendships never sever, there really is no resolution given for the strain he puts on his friendships. The next thing that happens is Mercutio is killed by Tybalt, and Benvolio stands up for Romeo by honestly reporting to Prince Escalus Romeo's precise involvement in what had just happened, especially that Romeo had tried to make peace. After Mercutio's death in Act 3, Scene 1, Benvolio is never seen again in the play, showing us that any strain on their friendship that Romeo caused was a very insignificant matter to Shakespeare.