Only reason why I know this tradition exists is because of an episode of Friends, as I had nothing else to binge while on an offshore rotation: Each trip involved being on a ship for five weeks straight with shoddy internet connection.
Blue is supposed to be the colour, yes. The verbiage is that "blue is an ancient symbol—dating back to Ancient Rome—representing love, purity, and fidelity". This is, however, absolute poppycock. Blue was a symbol of fidelity, this is true, but to the emperor, not in love. And indeed there is no single colour that symbolizes all three things in Roman times.
White symbolized purity and innocence.
Yellow represented marriage and fidelity.
Red represented violence (Mars), yes, but also passion and love.
Green represented beauty, fertility, and love.
Purple represented passion, but chiefly reserved for the royal classes.
Blue was not related to any kind of love symbolism whatsoever. The Victorians just made stuff up. Again. Like the so-called "medieval" torture devices (like iron maidens, etc.)