I expect this to change as more ascensions are released. Each character’s principle must align with the principle of your desire.

If you don't know yet, to romance a follower you must recruit them, then talk to them, and as the subject of the talk take them to either Oriflammes Auction House (AH), Ecdysis Club (Club), or Strange Streets by Moonlight (Streets) item code locationstreetsstrange.

The format is name, location to take them, and which desire they are compatible with.

Renira, Club, Sensation
Saliba, Club, Sensation
Rose, Club, Sensation
Victor, Club, Sensation
Violet, Club, Sensation

Elridge, AH, Power
Tristan, AH, Power
Valciane, AH, Power
Laidlaw, AH, Power

Clovette, Club, Change
Leo, Club, Change
Dorothy, Club, Change
Sylvia, Club, Change
Ysabet, Club, Change
Porter, Club, Change

Auclair, Streets, Enlightenment
Clifton, Streets, Enlightenment
Slee, Streets, Enlightenment
Cat, Streets, Enlightenment
Enid, Streets, Enlightenment
Neville, Streets, Enlightenment

What's odd here is that Winter and Edge are split.

If you are achievement farming for these, I highly recommend some save manipulation. Create a baseline save with all your acquaintances and emptied out book stores; but before you found your cult. At this point you can just go in set your desire, found your cult, ascend, then copy and reuse an end-game save to get your ever after achievements.

Save are located at C:\Users\{yourUser}\AppData\LocalLow\Weather Factory\Cultist Simulator

Lovers must die of wounds and be resurrected to ascend with you. You can either send them on expeditions until they have 3 scars or let them get one scar and die during a season of sickness. Immediately resurrect them and ascend to get the achievement.