Having a similar issues with 2 teen couples in my game. Once their friendship maxed out all their romance options dissapeard. No dates, kisses, nothing even when very flirty. I've also noticed the romance options don't appear when interacting with other sims they aren't in relationships with
I have a couple of suggested causes:
1. Are both of your teen couples still teens? If one of the teens ages up to young adult all romance options will be locked out until they're the same age.
2. There's a bug where couples, usually same-sex couples, randomly become siblings. This is especially disconcerting when it happens to married couples with children, as my friend can attest.
