If ever there was a confusing play for the answer to this question, it is Midsummer Night's Dream. First of all, it is important to remember that this play is meant to be, as Puck tells us, only a dream.
If we shadows have offended,
Think but this, and all is mended,
That you have but slumber'd here(420)
While these visions did appear.
And this weak and idle theme,
No more yielding but a dream, (V.i.)
It is not supposed to reflect reality. Puck is saying that this play has been only entertainment -- and, if it did not entertain, we should give it no more attention than a dream (there is the extended play on "dream" too, here, as much of the play is about sleeping, waking, and dreaming). This is a silly play, which, nevertheless, contains some important human truths. But, I believe, the definition of romantic love in its perfection is not contained in it -- perhaps because Shakespeare believed in various kinds of "true" or "romantic" love, as the station and personality of the lovers might require.
Let us consider the pairs: there is Theseus and Hippolyta, the older couple who represents authority; Hermia and Lysander, the couple who represents the triangle at the beginning of the play (Hermia having two lovers, Lysander and Demetrius); and there is Helena, the odd woman out, who loves Demetrius and represents unrequited love. In addition, there is the feud between the supernatural couple of Titania and Oberon (with the hilarious addition of Bottom, as the fool), king and queen of the fairies, who, incredibly, represent marital love.
Through the various switchings and confusion of the night spent in the forest of Arden, a few things remain constant. Theseus and Hippolyta, who are well-suited for each other both in temperament and in rank (the latter being the more important, since both of these people are rulers) remain steadfast to each other. Their harmony brings joy and prosperity to their people. They do disagree slightly, but it is most important that they be in accord with each other not just for themselves, but for the good of the populace. This is not a picture of romantic love as we might imagine it today -- the suitability and harmony of this couple is not simply a personal matter, but a political one.
Hermia and Lysander had great difficulties to overcome, but in the end it is their youth and innocence which seem to soften Theseus' heart and save them from the wrath of Egeus. So, too, with Helena and Demetrius, though Demetrius has to be drugged to be in love with Helena. The constant here with these young lovers is that, at this age, love is fickle and foolish (especially in the case of young men) and must be helped along. It is interesting to note that both Helena and Hermia get their original desire -- while Demetrius's love for Helena must be overriden by the love juice so that Helena may have him. It appears that Shakespeare is saying that it is more important that young women have their way -- men can be swayed!
Titania and Oberon represent a kind of mature love, which has hit a rocky patch. The resolution of this is disturbing, however, for Oberon drugs his wife and makes a fool of her, so that she may give in to him. It appears that in Shakespeare's eyes, the man's will must dominate after marriage.