Girls have always been taught that men are the strongest gender and that women should be respectful to them. We are taught that they are the one in charge and such things. The fact that they are physically stronger doesn't mean anything. When a girl gets in an abusive relationship, the fear and this respectful and submissive behaviour is the reason she stays in the relationship.
I believe that many other reasons can come to play such as, fear, children and extent/type of abuse.
Whilst love may be a reason, I think many other factors may overtake it.
I don't understand how you could love someone who is abusive, however, I have never experienced abuse of any kind and do not judge any one who is in that situation.
I doubt very much they will still truly love who they are with. Perhaps they have tried to make themselves believe they love their partner so they receive less beatings - emotional or physical, but it all links down to fear of what would happen to them if they -tried- to leave.
A lot of girls, including me, don't even believe in love. Sometimes a girl will start dating a guy that she only thinks is nice and kind when he's not. When the guy starts getting abusive the girl normally stays in the relationship cause the guy normally threatens to hurt or even kill the girl if she doesn't stay with him. Because of that the girl stays in the relationship scared they might get hurt if not.