Both Shakespeare and Jane Austen portray love within love triangles as a hardship for at least one member of the triangle. One thing they share in common is that within the love triangles in both Romeo and Juliet and Pride and Prejudice it is one of the men in the triangles that takes the worst blow.
The love triangle Shakespeare portrays in Romeo and Juliet consists of Juliet, Romeo, and Paris. We learn that Paris truly does deeply love Juliet and, by the end of the play, we see him in profound mourning. We see him visit Juliet's tomb late at night to privately cry and "strew" flowers on her tomb, as we see in the lines,
Sweet flower, with flowers thy bridal bed I strew
(O woe! thy canopy is dust and stones)
Which with sweet water nightly I will dew;
Or, wanting that, with tears distill'd by moans
Nightly shall be to strew thy grave and weep. (12-17)
These lines show us that Paris is truly in grief and that he truly did love Juliet, but not only that, we see that Paris is the one in the love triangle who took a blow from love by loosing Juliet to death and by loosing Juliet to Romeo.
Similarly, in Pride and Prejudice, one prominent love triangle is between Elizabeth, Darcy, and Mr. Collins. Although, like Paris, Mr. Collins is the one who suffers due to love, Mr. Collins's suffering is not truly genuine, nor is it long lasting. Mr. Collins chooses Elizabeth as a wife because Lady Catherine has told him to marry, because she is beautiful, and because he wants to do a service to the Bennet family by keeping the entailed estate in the Bennet family through marriage (Vol. 1, Ch. 15). Elizabeth knows very well that his professed affections for Elizabeth are not truly genuine, as we see in the line,
The idea of Mr. Collins, with all his solemn composure, being run away with by his feelings, made Elizabeth so near laughing.... (Vol. 1, Ch. 19)
While Mr. Collins's pride is very much hurt by Elizabeth's refusal, because his love is not as genuine as Paris's, he quickly recovers and soon proposes to Charlotte Lucas instead.
Hence, in both love triangles, the authors choose to show gentleman characters as being hurt by love, though the story lines and characters are very different.