According to Toby, why does he only want to date women his own age?

Contrary to the majority of the men around him, Toby is not interested in dating the younger women and screens the women he dates by keeping the age on his dating apps to only engage with 40-50 year-old women. Toby claims that the younger woman "made him feel like he wanted to die" (26). He thinks that these women have too much optimism.