AITAH for refusing to switch seats on a plane, even though a mom started crying?

So, I (27M) was on a long-haul flight, about 10 hours, and I had booked a window seat months in advance. I get motion sickness, and the window helps a lot. Plus, I was planning to sleep for most of the flight.

When I got to my seat, a woman (maybe mid-30s) was sitting there with her baby on her lap. I politely told her that she was in my seat, and she immediately looked uncomfortable. She said she thought it would be okay since she wanted to sit with her husband, who was in the middle seat next to her. I asked where her original seat was—turns out, she was supposed to be in the middle seat of the row behind us.

She asked if I could just take her seat so she could sit with her husband and baby. I glanced back and saw her seat was squished in between two big guys, and I already knew that wasn’t gonna work for me. I apologized and told her that I really preferred to keep my assigned seat.

She kept insisting, saying, “It’s just a seat,” and “I’m a mother traveling with a baby.” The husband wasn’t really saying anything, just giving me a guilty look. A flight attendant came over because she was getting upset, and when I explained the situation, the attendant told her she had to sit in her assigned seat if I wasn’t willing to switch.

Then, she started crying. Not like full-on sobbing, but she looked really frustrated and kept shaking her head like I was some kind of monster. I felt bad, but also, I paid for this seat and specifically booked it early. The guy next to me whispered, “Good for you, man. People always try to pull this.”

After takeoff, I put my headphones in and tried to sleep, but I could feel the people behind me glaring. When we landed, the husband mumbled, “Must be nice to have no empathy,” as I grabbed my bag.

AITAH for not giving up my seat?