Is AUTHOR wrong in the post ? POST : So first for a little background. My roommate[21m] and I[20m] are currently renting out a 3 bedroom apartment in our college town until the end of May. During this time and prior, as we have been roommates for a few years now, we would go halves on certain items that we both wanted and would use. When time came to part ways for breaks and such we would decide who gets the item and weather or not the other person wanted to be bought out of their share giving full ownership to the other party. This also the case if said item were to break under the possession of one of us and it has worked until this morning. 

Last night i decided to bring one of our shared items to our friends house and it unfortunately broke. I knew i'd be responsible for paying back my roommate for his half and i'd accepted that fully.

Heres the problem:
When i told him this he became visibly upset (understandable) but tried talking to me in a calm manor. According to him since i didnt inform him that i was taking the item to our friends house and then broken it i am even more responsible for it breaking. He is demanding i pay him back his half for the item ($25 ) in addition to more money to compensate him for his loss (unspecified, probably more than $10). If i refuse to pay him back extra hes going to refuse to pay me back for other items we are currently sharing and keep said items. I told him I refuse to pay him more money than he invested as he is walking away having lost nothing and i would be down $50 and the item, worse off than i would be if i bought him out normally. 

So i need to know reddit, AITA for refusing to pay him more than his initial investment??