So my girlfriend and I have been together for a year now. She has a 4 year old daughter. Her daughter at first was great. She was a blast to be around, always polite and never fused, acted out or anything. Recently she started spending every night with us (before she would spend 2-3 nights away at either of her grandmas houses or her aunt she was close to). Ever since we moved into our new place her daughter, I'll call her M, has been a nightmare.