To preface this, I have very low self esteem from an abusive childhood and equally abusive relationships, so I am very much aware that a lot of things in my head are bigger than they probably are in reality. But I've had a fair bit of therapy and other interventions and am quite confused now as to whether this is normal.
My boyfriend of about 6 months has a , shall we say, colourful past - he cheated once when he was still a teenager, had a few relationships with 2 partners (who were all fully aware at the time) at the same time, but also had fully monogamous phases. Relationships generally lasted around the 2-year mark; he is now mid-20s, I am older by a few years and have only been in monogamous relationships of between a few months and up to 8 years.
We are both committed to the relationship, speak several times daily, see each other almost daily (despite about a 30min distance) and there are few to no issues in the relationship as such. We have had the exclusivity chat, the future chat etc. and are broadly in line with each other's wishes.
BUT. He has an ex, his last one before me. They are on speaking terms and before he and I went exclusive still had casual sex after their break-up, which had happened about 7 months before we got together. I know she would still quite happily jump him. She helped him through a very difficult stage in life when they were together. She left him, in the end, but they remained friends. They used to talk about once a week and meet up once every few months. She lives an about 4h drive away.
When he and I first got together she still wanted to sleep with him and he and she only agreed not to out of respect for her (then) boyfriend. That was before he and I had the exclusivity chat.
It has now occurred that he is WFH and she is in self-isolation. I have realised that they now talk every day via phone, for about 30min-1 hour every day. I feel threatened by this.
He is incredibly reassuring and patient, knows that I have a lot of issues and for the most part, happily talks me through this and keeps saying they are just friends. I have been cheated on in the past, so I know that this is most likely me.
But am I unreasonable in feeling uncomfortable? I just can't shake the thought that she still has feelings for him. She never slept with the guy she was seeing for months, but would have quite happily still have slept with my partner. They talk so much right now. I don't want to make him choose, that would not be fair. I do not want to dictate his friendships. In a way, it's good he is still on good terms with an ex - it shows me that he is a good guy. But is it all just me?
Please be gentle.