A couple different aspects of love that we see Shakespeare express in A Midsummer Night's Dream are fickleness and infidelity. Since Shakespeare entwines the aspects of love with his theme of reality vs. illusion, he shows us that love is only as real as a person makes it and that it is also an irrational emotion.
We especially see the aspect of fickleness being entwined with the theme of reality vs. illusion with respect to the four young Athenian lovers. At the beginning of the play, Lysander and Hermia believe that they are genuinely in love and cannot be divided. However, Puck shows them that this is actually not the reality and that even Lysander is capable of being fickle. Puck uses the magic flower to make Lysander fall in love with Helena, turning his love for Hermia into an illusion. Not only that, since his love for Helena is magically induced, we see that even this love, regardless of what Lysander thinks, is also an illusion. In fact, Lysander believes that his reason has guided him to believe that Helena is the better woman for him than Hermia, as we see in his lines, "The will of man is by his reason sway'd, / And reason says you are the worthier maid" (II.ii.117-118). However, Lysander's fickle nature has not been guided by his reason as he thinks it has; he has instead been influenced by an outside source, showing us that, not only is love an illusion, it is also an irrational emotion, one that is not governed by the rational mind.
The aspect of infidelity is especially portrayed through Oberon and Titania. Literary critic Shirley Nelson Garner points out that Titania's love for the beautiful Indian changeling boy actually borders on the erotic. We know that it is erotic because Puck describes Titania as crowning the boy with flowers and making "him all her joy," which happens to be the exact same way she treats Bottom when she falls in love with him (II.i.27). Since her affection for the boy can be perceived as erotic, it makes sense that Oberon is jealous and that the boy has created a severe problem in their marriage. Oberon distracts her with falling in love with a foul creature in order to regain her love for him. We know that Oberon's scheme works because she releases the boy, and when she awakens from the spell, everything is mended between her and Oberon. The fact that Titania allowed her love for another to come between her and her husband shows us that their love was only as real as she made it; it was ultimately an illusion. Likewise, the fact that she released the boy so easily also shows us that even her love for the boy was an illusion. However, the fact that Oberon was able to repair their marriage shows us that their love was as strong as he was able to make it. In other words, Shakespeare is showing us that love may be an illusion, but it is any illusion one wants it to be.
In my opinion, Shakespeare's concept of love, as shown in this play is as follows:
"Love looks not with the eyes but with the mind..."
This indicates that Shakespeare is of the opinion that one should love someone for who they are, and not for their appearance.
I also noticed that the women in this play are not submissive, as was expected in that time. Shakespeare does not appear to expect a woman to be submissive and it seems he would rather that they were strong and independent thinkers.
The success of Hermia being allowed to marry Lysander, who she loves indicates that Shakespeare thought people should be allowed to marry those that they loved. Neither the rank of a person nor the opinions of others, should stop two lovers from marrying.
At the same time Shakespeare contrasts this theme with Helena, who love Demetrius but Demetrius was tricked into loving Helena.
A further contrast to this theme is Hippolyta who was won by sword and not love.
"The course of true love never did run smooth".