I have a question. In the season six episode "Theo's Dirty Laundry," Theo was 19 years old and it was revealed that he had moved in with his girlfriend Justine and Cliff and Clair were not happy about it. They threatened to cut off his expenses for living and school and everything if he didn't stop living with Justine. Yet, in the season eight episode "With This Ring" Vanessa was 18 years old and was revealed to be engaged to 29 year old Dabnis for six months, meaning she had gotten engaged at 17 and she was just now telling them. Yet Cliff and Clair didn't threaten to cut her off. Why was it OK for Vanessa to be 18 and engaged to a 29 year old but it wasn't OK for Theo to be 19 and simply living with his girlfriend, who is the same age as him presumably? That makes no sense.

A couple that lives together is likely having sex. Sex outside of marriage is frowned upon by a lot of people.

Yes but Vanessa and Dabnis mentioned they had been spending time in his house plus Cliff didn't seem to mind when Theo once said he had all night at Justine's in one episode. He laughed and teased him about it.