Ex games 🙄🤔😟

My boyfriend and I have been dating for a few months now it hasn't been very long. We have been best friends for about 5 years so we have a lot of history, he has had 2 gf's in the past while we were friends back in high school (we are in college now) but the last girlfriend he had was really jealous of me because we were so close... Anyways they were and off and on thing, had a really unhealthy relationship. One time she made him stop talking to me for whatever reason idk. And we did stop talking for about 4 months. Then they had broke up a little while after that. It's been about a year and a half since then. When he asked me out of course happy but also very unsure the main factor being her, she's always seems to just pop up🙄. I know for a fact they are going to talk again and she's going to try everything to get him back. I really don't want her to ruin anything we have because its good I can feel it! What should I do about her? Should I talk to her .. I am not going to tell him he can't talk to her if it ever comes up, but I feel she needs to know from me where we stand.

Background info:

- I was genuinely just his friend when they were together no relations involved! ( I was a virgin during that time) 

-his ex and I don't like each other at all and I don't trust her 

-she cheated on him with one of his close friends and another guy