I got a fake boyfriend to fend off a family arranged marriage.

Fake it till you make it

Daily interactions can use the DS small model; for important plot points, it is recommended to use advanced models (DS V4 for high CP/claude, if you want to push it a bit, try Gemini).
Remember to write user notes for important matters, do not trust AI's memory.

Fixed elements are only family background, fixed friends, and how long they've known each other; customize the rest. If you can argue your way through it, BL should also be possible, no sexual orientation restrictions.

Addendum:
!Gift can make him give small gifts, just use it in the conversation.
!if can jump to various situations, you can type "!if get married and go on honeymoon" etc.