Hmmm, the problem was not the horse it seems: I have the CtD every time I draw a weapon.
Edit: The game does not crash when I draw a two-handed weapon and also not when I draw a one-handed weapon and have no shield. It only crashes when I draw a one-handed weapon and when I am carrying the shield, so I suppose the shield is the cause of the crash.
OK, I enabled the mounted combat again for some more testing, and I can confirm the above: the crash is caused by drawing the shield.
Last Edit: Jun 4, 2017 16:27:23 GMT 1 by oldboar: Added info