They ignore your boundaries.
One common symptom of sociopathy is a disregard for the personal space and feelings of others. You may express to them certain boundaries, but due to their condition may not truly grasp the impact they're having on you.
They can be frighteningly aggressive.
Sociopaths aren't often too concerned with the feelings of others which often leads them to be brutal and sometimes frighteningly aggressive with the people and things in their lives.
They manipulate you.
Manipulation isn't universal among sociopaths, but it certainly can happen. They have little regard for how their actions may impact others and tend to do things in a knee-jerk fashion, leaving them feeling guiltless about what they've done.
You feel unloved.
Some sociopaths don't have the capacity to love and feel normal human emotions. As a result, many of their relationships are functional, utilitarian affairs. It can leave you feeling unloved.
Sociopaths don't tend to feel bad when they've done something harmful, like lying. For this reason, sociopaths often have no problems with lying, not just to you, but to themselves as well.
They keep you from people you love.
A manipulative sociopath will attempt to guilt trip you about doing things you love to do with the people you love if they don't want to go with you. They'll accuse you of abandonment or even worse. Don't let them guilt you.