She could be very private about that aspect of her life.
I'm the type of person who makes disgusting jokes especially about sex. However, when it comes to discussing it with anyone whether it be a family member, close friend or boyfriend/girlfriend, I get very uncomfortable and awkward.
I'm not saying Ruby is the same as me, she definitely does not strike me as the type to have a dark sense of humour. However, she does strike me as quite private when it comes to certain things and I reckon that's one of them.
We're not obligated to know I guess as she is a StudyTube channel.
(Just my opinion!)