The Romantic era (1800-1850) in music is typically characterized by larger pieces of work that start to incorporate bigger orchestras with bigger sounds.
This music places a strong emphasis on "stirring emotions" within the listener, and does not necessarily have to do with the emotion of "love".
Romantic composers achieve this by writing more complicated music; using key changes, dissonance, and chromaticism more frequently. This largely was made possible by advancements in the instruments they played, as well as in music theory and teachings on how to write music.
Beethoven is largely credited for bringing music into this new style, and we often turn to his 3rd symphony for examples of this. Some other notable Romantic composers were Schumann, Chopin, Rossini and Tchaikovsky.
Here are some characteristics of Romantic music:
-Intense expression of emotion
-More freedom in the structure (form) of the music
-More complex use of tone and rhythm
-Larger orchestras/developments in wind instruments
-Greater technical virtuosity
-Sense of "Nationalism" in musical styles
-Links music with other art forms
I hope that helps as a starting point! If you listen to some of these composers and compare them to the works of Mozart or Bach, for example, you will be able to hear the stylistic differences.