AITA for not telling my Dad's girlfriend that she is allergic to seafood?

My parents have been dating for a few months and things are getting pretty serious. Her daughters are super excited and want them to move in together and marry. My dad and his girlfriend are taking things slow, but she moved into our house a few weeks ago. <br><br>My girlfriend and I currently live in the basement of my parents house. We pay no rent and have been saving a ton of money. We are considering purchasing our first home soon.<br><br>I am a cook in a nice restaurant so I get some pretty good take out deals. We have had a lot of seafood in the house since my dad and his girlfriend love it so much. My girlfriend on the other hand is not a fan, which is because she is severely allergic. It has caused her to have really bad stomach cramps. Since we've had a lot of seafood in the house recently she has had a ton of cramps and has been in a really bad mood.<br><br>I just found out about her allergy yesterday. I told my dad and he was really upset to find out, since his girlfriend loves to have my girlfriend over and they do a lot of cooking together. He told me that I'm an asshole for knowing about her allergy and not telling me, and I appreciate you all's thoughts. I'm also upset that they are so close to the wedding time frame and they will have to either not invite my girlfriend or not have any of the food they cooked together at the wedding.