Tita and Pedro- Question (Spoilers)
They had sex and then she thought she was pregnant. Then they continued to abstain until the final scene when they had sex?
In the book it's a little more complicated. After Tita breaks her engagement with John, Rosaura allows Tita to stay in the house and have a secretive relationship with Pedro, so long as they are not obvious about it. Their final love scene in the book is in a celebration that they can finally live openly together.
"Any idiot can face a crisis, it is this day-to-day living that wears you out". Chekhov