if you check out civinfo you will find lots of problems with Civic clutches slipping "before their time". Might be the same with Accords.
I have a 56 Civic diesel, bought with 27k on the clock 6 months ago. I have had to have the clutch replaced due to slipping in similar circumstances to you. The car was out of the manufacturer's warranty so I had to cough up the labour, even though they did pay for the clutch as a gesture of good will (if ever there was a euphemism for owning up to the problem!).
Apparently there are stories of Civic Type R clutches going in 2000 miles 😯
That said, at 70000 miles you've not done too bad, but it is an engine out job