Big dick, wont last...

So I've started dating someone new, and obviously I know theres gonna be an adjustment period where we're still gettin used to how we fit together. This man is blessed in the size department, and I love it. Except for the fact that I cant use it... We get goin, and everything feels great, but if we pick up any speed, & I mean ANY speed at all, it goes off... Every single fucking time! And because of that, I havnt been able to cum once since weve been together, and I dont wanna make him feel bad or anything, but its startin to piss me off cuz I'm gettin "blue balls" every time. I'm normally a very blunt person, but idk how to handle this, cuz I really like HIM & I wanna be with him. His dick is just pissin me off...