AITAH for telling my ex gf im gay when im really not?

I (m20) was dating (f20) for a few months, we dated for like a yearish in high school previously. I’m going to make this post blunt to not waste anyone’s time but she is not financially responsible at all, she spends hundreds of dollars on a single persons holiday gift for ONE holiday. Shes a messy person i am not. She constantly told me that “you hate me” or “you want me to die” over the slightest inconvenience. Her step dad was an asshole to me constantly over both our relationships.

She wants kids and marriage and i don’t. (i work in family law if that makes sense)

To avoid her feeling bad i told her im gay(im bisexual with a preference for men so it’s not unbelievable.

Am i wrong?