A book that will allow to you to take a step back on what you always thought about sex and orgasm.
I see you are a part of Nofap, stay strong brother :)
Maybe you could try karezza? It takes a complete rethinking of sex, but changing out your style of sex could help him a) last longer and b) give you more frequent, longer sex.
Some people freak out when they see sex with no orgasms? Isn't that nuts? It can actually work really great and leave you feeling very satisfied and most importantly, MUCH closer to your SO.
This is a good book to read to learn all about it: *Cupid's Poisoned Arrow: From Habit to Harmony in Sexual Relationships