Help!!!

I need some advice on what I can do to help my BF be better in bed. I've tried saying something... and nothing was done. He is perfect in every way except a couple things. One of them being he isnt very big and doesn't last but a minute. Second is that he is a BIG man and I am a tiny woman so trying different stuff is almost off the table. I want this to work but am at my wits end with how to fix this. I dont want to be too blunt so if I left any important stuff out, just ask. I just need some advice on shorties and how to work around the fact hes 3-4 times my size.