The original sound track of LOVE³ - Love Cube - has been released as a DLC. More details are available at the DLC Store Page.
https://store.steampowered.com/app/1132060/LOVE_Love_Cube_Original_Soundtrack/
8/4 Update: Fixed installation issue
It turns out that our DLC build had a problem causing it not installing properly. We have fixed this issue. Soundtrack DLC should start to download automatically on next startup. If Steam client is currently running, please quit and relaunch Steam.