Who would have been to blame in this case?

I don’t know if it’s the right forum for this, but I have a question about road traffic rules. I drove on a 3 lane road this morning, the right was the bus lane, the bus changed to the middle lane and since I wanted to turn right, I changed to the bus lane – from the bus I wanted to drive the remaining 20m to the intersection covered, but just before the intersection is still a driveway – just before I passed the driveway – I had to take a full braking mac because someone from the opposite lane wanted to drive into the driveway – I couldn’t see him at all – only reacted quickly. And the one who wanted to enter the driveway turned off in front of the bus. Who would have been to blame in this case, the bender who didn’t pay attention to me? Or me – who changed to the bus lane? How is that if the bus lane is still “active”, can I then go on the bus lane to turn off or do I have to turn off from the middle lane? Sorry if the text is a bit confused, but it’s already quite late… Greetings Bonatus…