The Lovers represent love (naturally), relationships, and the alignment of values. Reversed, it represents self-love, disharmony, and misaligned values. I think that Rainbow Dash and Applejack represent this well — they are quite in tune on things like loyalty to their loved ones, hard work toward achieving goals, cider, and athleticism, but on the flip side, they share a competitive nature that can drive them to fighting, and their values can stand in opposition to one another.

Honestly, I had to play a little fast and loose with the symbolism in this card. There's a lot of religious symbology in the Lovers, traditionally, including a literal angel and the Garden of Eden, and I didn't feel that would translate well into a pony-based context. Also, I just didn't feel comfortable trying. So, I went my own way. The sun, which may be seen as rising or setting, can be interpreted as a symbol of power and passion, one which can be ascending as a relationship increases in passion, or descending as it settles into stability. The tree in the background is there literally to represent the love story of Applejack's parents, and metaphorically to show the abundant fruits of a relationship well-tended, each partner giving time, energy, and support to the other.