Why do I need to log in everytime I try to play minecraft

Every time I start minecraft, I need to put all my details in again, this never happened before the last launcher update but now it is a constant thing, if you have a solution please let me know, it is very annoying, and I can see one day when I go to log in it will tell me my password or email address is wrong, which has happened in the past even though they are both correct, any solutions..