Not all condoms are created equal, of course. If you’re going for maximum sensation, choose any extra-thin style.
If that’s not cutting it, look into custom-fit condoms—guys aren’t all the same size, so it makes sense that guys shouldn’t all use the same condom. Lucky Bloke is a good online condom retailer that specializes in custom fitting. (It sounds crazy, but you measure yourself at home with a toilet-paper roll, and follow their instructions. Just trust me on this.) Another thing that helps is putting a dab of lube on the inside of the condom.
But if you’ve tried all these things and still can’t get off, then your next question should be how to ask her to finish you some other way.