My SO won't have sex with me any more

Katherine
I've tried everything to spice it up in the bedroom with my SO And nothing works we go months without having sex and when we do have it its for 10 minutes and I just lay there. I try and get him to do foreplay and everything else but in the end I just do it myself. It's upsetting. I just want to know why I ask him but he gets upset with me and just leaves. Should I leave? Should I be worried. I don't know!