Work place bullying meets family politics

I am 21 and I work with my 34 year old boyfriend. We also work with his mother who isn't his boss but my supervisor. and also a guy who use to be my best friend but stabbed me in the back several times cause I wouldn't date him. Ok the bullying from my ex-friend started when I started dating someone else and not him. (the relationship I had before my current boyfriend) which only lasted about three months because he had to go away on work placement for university and then his job as he would be traveling and wouldn't be around to be with me. mere days after my ex broke up with me I was having what I thought was a conversation with my friend via text. seconds later I get a rude and rather upsetting series of texts from an unknown number. little did the sender know that I was aware of who they where. she was my ex's girlfriend (My relationship previous to the ex who broke up due to his uni and work) she said that I was emo and that it was "Ok for [me] to be angry at the world just don't tell anyone about it" and "I think that work placement is code for getting away from you" I came home from work in tears and my mother asked me why I left my phone on the kitchen table by mistake and my mum obviously saw the texts and called and confronted the people who where doing this to me. I was right it was who I thought it was. but my ex-friend didn't stop there he then found out I was seeing my current boyfriend and then spread rumors about us telling almost everyone. including our supervisor who is my boyfriends mother. My boyfriends mother straight away started to attack the both of us discreetly as she "Monitored" my "performance" at work only to take a personal jab at me for crying (I had cried at work once before due to my ex braking up with me) she also told me that I had an attitude problem and pulled faces at people who where higher up from me. she also said that I was talking too much and moved me across the office closer to her and put more people in the corner where I use to sit (whom might I add make much more noise then I ever did talking to the phew people around me) she's been personally attacking my boyfriend about our relationship directly as she pulls him away from his work to talk to him. she starts off by saying one small thing abouot work and then jumps into some personal attack. be it his childhood, his father (whom she has divorced) my boyfriend doesn't want to become his father (as his father use to beat my boyfriend and his siblings when they where younger and sometimes his mother would join in) she tells him about who she thinks is perfect for him to date and even suggested she set him up with someone else. even my ex-friend suggested he was going to set my boyfriend up with someone else too. she messed with my boyfriends head so much I caught him talking to other women. how do I stop her from playing mind games with my boyfriend and get these two horrible people to stop surely there is a way legally that we can stop her with out me losing my job. Please Help :'(