In these lines, Shakespeare is saying that true love is never going to come easy, there are always going to be barriers based on all tales of love in history.
A theme related to love in this play would be that love can overcome all obstacles. Two characters that prove this are Hermia and Lysander. Hermia and Lysander have to overcome the fact that Hermia's father does not want them to get married. They run away to the woods, thinking they can escape the Athenian law, but in the woods more trouble comes their way. After they make it through all of Puck's mischief, they are woken by Theseus and Egeus at the edge of the wood. Thankfully, since the theme is how love can succeed and overcome obstacles, Theseus says
"Fair lovers, you are fortunately met:
Of this discourse we more will hear anon.
Egeus, I will overbear your will;
For in the temple by and by with us
These couples shall eternally be knit:"
This is his invitation to Hermia and Lysander along with Helena and Demetrius that he is going to overrule Hermia's father and let both couples be married alongside himself and Hippolyta.
