Should I let my parents meet our daughter (read below..long story)

So, my SO and I had a daughter, she's 16 months now. My parents have never met her. They want to though. But here's the back story. When my SO and I first got together 4 years ago he was nothing but judged my mother nonstop she was constantly talking behind his back calling him names and making up lies. So finally my SO got fed up with it...he decided to have a sit down meeting with my parents about it all and told them if they ever had anything to say he's fine with them saying it to his face. Ok so my parents agreed. Then about a week goes by and it starts over again from my mom, talking smack, blabbing her mouth as usual. My SO finally decides the bridge is broken and chooses to just not care anymore, he tried his best. So he just never sees my parents again after that. My mom continues to bash and trash talk about him to me...all lies. Ok now flash forward to now, my parents want to come to where we live and meet our daughter and this whole time they've made no attempt and trying to fix things with my SO. My SO said hell no they aren't meeting our daughter until somethings get fixed and they work on the relationship with me first. My parents are really upset about it. I feel bad for them, especially ny dad seeing as how he didnt any thing. But I want your opinions....should my parents be able to meet our daughter even though things haven't been mended with my SO?