There are many songs you can listen to when you are "crushing" or in love. The ones I'll mention are the ones I listen to. They make me happy, relaxed and or emotional.
The first one is titled "Dein ist mein ganzes herz/You are my heart's delight". It's a song composed by Franz Lehar, the lyrics are about admiring someone. There are German, English and Italian versions.
The next song is a song from a video game called "Medal of Honor: Underground". The song's name is called "Er lässt mich niemals allein/Each night he comes home to me", it's Composed my Michael Giacchino. The song is about a woman who remembers her husband who died in a war. It's a sad song that made me emotional when I first heard it.
"Marion's theme" from "Indiana Jones" is a great instrumental love song. It's named after the woman Indiana Jones falls in love with. It was composed by John Williams. One of the popular versions is played during the "Raider's march", which was also composed by John Williams. The version below is played when Marion tends to Indiana's wounds.
If you like this genre of music you might like the songs I just mentioned. Anyways, that wraps up this mytake. I hope you enjoy these songs.