If your Sim won’t do romantic interactions, this usually indicates their relationship bar is not high enough. Keep using friendly and funny interactions until romantic interactions become available.
Equally important, make sure both Sims are in a good mood and their needs are in the green.
If romantic interactions are still unavailable, maybe the romantic preferences of the Sims involved are not compatible.
Sims will be attracted to only one gender, the other, both, or neither. Some Sims are not at all interested in having romantic relationships.
Sims will be reluctant to use romantic interactions with a Sim of a gender that goes against their orientation.
Adults and teens can not have romantic interactions. If your adult Sim is interacting with a teenager, the Romance menu is unavailable.
On the other hand, teens can use romantic interactions with other teens once the romance bar is high enough.
If certain social interactions are missing in The Sims 4, this usually indicates your mods are outdated or corrupted.
Maybe this is a glitch
If your Sims can’t do romantic interactions due to unexpected technical glitches, reset them, move your Mods folder to your desktop, and repair your game files.
To reset your Sims, press Ctrl, Shift, and C and type in testingcheats true. Hit Enter to enable cheat codes. Then, type in resetSim Firstname Lastname (the full name of the Sim you want to reset), and hit Enter.
Move the Mods folder to your desktop and check if romantic interactions are available now. Maybe one of your mods is acting up.
If romantic interactions are available after moving the Mods folder to your desktop, this indicates one of your mods is the culprit.
Move your mods back to the main folder one by one and test your game to identify the culprit.
Don’t forget to update your game and mods to the latest version.
If the issue persists, go to your Origin Library, right-click on The Sims 4, and select Repair Game.
Restart the game and check the results.
Hope something helps.