Boyfriend nuts in 10secs

Okay so every time me and my soon to be fiancé (I’m the one proposing) have sex he always nuts in 10 secs tops🤦🏾‍♀️. I always tell him it’s fine and there’s nothing that he can do about it but sometimes when I have to wait a long time to have sex with him he just pass out after he nuts leaving me to make myself cum🤦🏾‍♀️. Lately I have been avoiding him and keeping to myself and every time he asks when we going to see each other I make up an excuse🥺. I need help on how to tell him how I feel about him nutting in 10 secs.