Cindy became pregnant when she was 17 years old. Despite being high school sweethearts, she became pregnant on purpose in order to trap Ruben into staying with her. When Ruben discovered this, he offered to marry Cindy, but she realized that he didn't really want to marry her & was offering out of obligation and turned him down.
Cindy told Ruben to stay out of her & Adrian's lives, but still received child support for him while Adrian was growing up. Cindy also harbored bitter feelings about Ruben having another family after Adrian's birth.
She became a flight attendant in order to support herself and Adrian on her own, because she hated relying on her parents, who felt that she had shamed them by getting pregnant out of wedlock as a teenager.
Cindy loves her daughter, but thinks that Adrian doesn't love her back even though she does. She was unaware of Adrian's affairs & her moniker as the "school slut" until Ruben told her.
Despite that, Cindy continued working, leaving Adrian unsupervised. She got a promotion at work which would've required her to move to New York, but turned it down so she could marry Ruben.
Cindy gets cold feet at first, but she and Ruben marry on the day before Leo Boykewich and Betty's wedding in a judge's office with Adrian as a witness. She wears a large ugly, flouncy red dress that Ruben's mother sent her.
When Adrian's pregnancy is revealed, Cindy tells her that she'll stand behind her daughter whether or not she decides to terminate her pregnancy which spawns an argument between herself & Ruben (who is against abortion).