Doves are most often associated with love and peace. Also a very common piece of dove imagery is the dove with the olive branch in its mouth.
If you weren’t aware already, the reason behind the branch is because of the story of Noah’s Ark were he releases a dove and it returns with a branch signaling the end of the flood. The early Christians in Rome used dove carrying an olive branch symbol as a symbol for peace. Another little piece of a religious knowledge is that in Christian imagery the dove represents the Holy Spirit.
You may have also noticed that doves are often used as symbols for non-aggressive/pacifist events due to their past. Further emphasizing their symbolism for peace.
Interesting fact for you, you can milk a dove. Seriously…they produce milk. It lasts longer than any other type of milk too, because no bugger will drink it (Red Dwarf reference there). No but seriously they do produce milk for their young, which must be painful seeing as they are breast feeding something with a pointy beak (just a joke they don’t have boobs really, that would just look weird. I think they feed it to them from their mouths) but that’s beside the point. This makes them a symbol of motherhood, family and nurturing.
Now to the love bit, Aphrodite (or Venus if you’re Roman) was often depicted as a curvy, beautiful woman with doves around her. It’s here we have early recorded evidence of doves being associated with love.
There’s not really much more to solidly associate them with love, but they are still widely a symbol of love. I suppose hanging out with the goddess of love is a good enough reason on its own but if that’s not enough, they make pretty nice “cooing” noises and they’re white so they look all pretty. So they just go nicely with love in general.