desperately need advice

i have been dating this guy for about 2 months now and have been one of his best friends for about 6 years. anyways he had a girlfriend before me (who wasn’t ever a friend of mine so no girl code broken here) and they dated for almost two years and broke up about a year and a half before he and i started dating.

throughout our relationship we have tried to be hush hush as there have been incidences where she has threatened suicide or flipped out at him because she’s seen him with another girl despite the fact that she has been with several guys in since they split and we want to avoid as much conflict as possible.

she’s obsessive to the point where if she sees our bitmojis on snapmaps in the same place she will bombard his phone berating him for it. every time we hang out he has to turn his phone off completely and be contacted via me because she will call him back to back constantly.

however i spent the night at his house and decided to give him a couple of hockey’s because i thought she had chilled down a little. he then went to work today and she approached him there and went ballistic at him when she saw them then sent him a bunch of his nudes from when they were dating threatening to spread them.

he’s stressing out like crazy and i have made a point to not interact with her as i don’t want to cause more shit for him or make the situation worse but this in particular is absolutely infuriating me and i frankly do not know what to do about it.

any advice or suggestions would be greatly appreciated :)