How can I make my Sims be in love/flirty with each other again

The Sims 4 Relationships Guide - Making Friends

Solved: Re: About flirting to friend sims - Page 2 - Answer HQ

The Sims 4 patch reminds Sims they don't want to have sex with family members

Maxis Match CC World — {Beta} Romance Autonomy + Faithfulness Traits

Scenarios - The Sims 4 Guide - IGN

The Sims 4 gender and sexual orientation customisation

The Sims Mobile - Be social and grow relationships in The Sims Mobile

The Sims 4 Scenario Playthrough: Finding Love After a Breakup

Trying to flirt with your sim's partner, someone barges in and suddenly is an awkward encounter. I find annoying that you can't kick people out of conversations, specially in public places.

Scenarios - The Sims 4 Guide - IGN