Help i need advice

My boyfriend n I been together for 5 yrs n his females cousin don't like me she made me had a miscarriage had many people want to fight me disrespect me all above. is it right for me to feel that my man shouldn't talk to her any more? after all that she have done n plus got him locked up just to get away from me so she could have his room leave her under clothes in his room thorn our in born baby pictures up then made me loss it.