I live in a 3BR 1BA house with a couple. I have one bedroom, the couple has the master bedroom, and all other space (including the spare bedroom) is shared. I have 1 dog and they have 1 dog. I have a covered parking space on the property and they have an uncovered space. We agreed at move in to split rent $950 me, $1,250 them based on this.

After moving in, the couple decided to have a baby (this was not discussed with me prior to moving in). They are taking over the spare bedroom for a nursery (72 SF of 2,200 SF of the house)

The couple only wants to reduce my rent by $50 for the additional space they’re using (this is less than the per SF cost of the guest room they are taking), and to make no rent changes due to the new baby. They argue that paying more rent on account of baby would be unfairly punitive to them, and that if I have anything major going on (like an exam to study for) they will try to take the baby out of the house so that I am not disturbed. I feel that I will regularly be disturbed (my bedroom shares a wall with nursery where the baby will sleep from age 6 mos. onwards), that this is a fundamental change to the occupants of the house/our living arrangement on which rent is based, and that my rent should be more significantly reduced because of this. AITA?