There are different paths to Heartsong's content? When and how do you make the choice between them?
Grain of salt and all that, can only tell you what I've seen. In Heartsong's third dream event, where she takes the form of the Elder, there are at least two possible resolutions. For the Control route, you have to take control of the dream by refusing to play along, then change the dream to training with Helayna instead. After that you can choose to bathe with Heartsong. You can also choose not to, not sure if that puts you on Control or not. Bathing with her will put you on Control regardless of what bathing options you take later during the sex scene.
For the Lovers route, you have to play along with Heartsong's facade as the Elder. You can tell her to stop after a certain point if you want, as long as you don't try to control the dream. Heartsong will offer to swear her loyalty to Rowan, which doesn't seem to change anything about the route.
From what I can tell, there's no way to switch routes once you've started one. Control has more sex scenes at the moment, and Rowan has more dominant dialog options with Heartsong, treating her more as a plaything or servant. Lovers has more caring dialog options and may have more sex scenes eventually. Heartsong also initiates scenes with Rowan instead of him only initiating them with her. Worth noting that Heartsong is happy with Rowan either way because she's been starstruck about him from the moment she first saw him in a memory Arzyl fed her. It's not clear at the moment if each route will end up in a different place, but I imagine Lovers Heartsong will not take it well if you side against Whitescar in the conflict between him and Arzyl.