I was in an abusive relationship two years ago, and all of these signs showed up.
1. Gaslighting
Blaming you for their actions. For example, "I only hit you because the way you dress makes me so mad".
2. Teasing (turning into bullying)
In the beginning, teasing may seem fun and cute, but if your S/O is still teasing you months into the relationship, especially about things you're insecure about, this is not okay. For example: "You're a little chubby. You could lose ten pounds".
3. Isolation
Sometimes the abuser will make sure that you don't go anywhere or that you are constantly with them. They will always try keep you occupied by you being with them. They will also make sure you are not on your phone as much as possible.
4. Paranoia about you or what you're doing
The abuser will always be paranoid about you or what you're doing. They'll always ask who you're texting, talking to, what you're doing. They'll even accuse you of cheating, lying, or being disloyal when you haven't been.
5. Jealousy
They are always jealous of the people you're around. My ex freaked out when he saw a guy come up to me in the library and talk to me. He even got jealous and beat me when my brother wanted to go out to dinner with me.
6. Threats
The abuser will make threats to keep you to stay or to intimidate you. For example, "I'll tell everyone you cheated on me if you tell people I hit you" (when you haven't cheated).
7. Jekyll and Hyde personality
An abuser will have a Jekyll and Hyde personality. They will be happy, romantic, sweet, and charming one minute; and the next angry, abusive, mean, and frightening.
Please, PLEASE, if you or someone you know, if you even suspect that you or someone else is an abusive relationship, please tell someone- like the authorities, or call the domestic abuse hotline at 1-800-799-7723.