Do I have the right to be mad??

Okay ladies so me and my BF have been together for 4 years , in 2015 he became friends with this girl and she instantly fell in love with him and I warned him about her , sooo we had broke up for like a month over something dumb and he started to lead her on and make her fall more in love with him because that was his way of going through the hurt I caused , so bam we ended up getting back together and she was really mad and tried to get him to leave me but it didn’t work, okay sooo , I lost my baby in 2016 with my bf and it has been the hardest thing ever , so one month after I lost my baby she had the nerve to say , “how many more babies you gone loose “ so automatically she had an ass beaten coming her way but friends and family held me back, okay sooo when I made him stop being friends with her I told him to cut all ties and he said he did , a few months ago I saw where he had liked her picture on IG and I told him if he does it again it’s a wrap , then a few weeks ago I saw he had followed her on snap , when I know I deleted her off his snap, and then a few sec ago I saw where he had once again liked her picture !!! I have every right to be mad right ?!? Cause I’m heated