In series three of Sex Education, Otis finds himself talking to Jeffrey (played by Joe Wilkinson) about his wife's increased sex drive following the death of her cat. Otis explains that many things can affect a person's libido, including grief, which can either increase it or decrease it.
Along with grief, the libido can also be affected by medication; contraception; health concerns such as anxiety, depression, or painful sex; and alcohol and drugs. To put things into perspective, "everyone's sex drive is different and there's no such thing as a 'normal' libido," according to the NHS.