How to stop being jealous/insecure?

[StellarLights]

I am a very jealous girlfriend.

I have never met my DP's Ex yet I have moments of being very jealous and insecure about her, mainly in the form of did he love her more than me? Does he find her more attractive? etc.

I am also jealous and insecure about anyone who my DP has slept with, ie. I'll see a picture of a woman that he's slept with and all I can see in my head is them two together.

I can't stand the thought of him being with anyone else.

He was also a bit dodgy when we were dating (not in a relationship but supposed to be exclusive!!) concerning another woman which doesn't help, and it got brought back up again when he tried to contact her recently to apologize for past transgressions despite it being a long time ago.

Anyway, I guess what I wanted to ask is how you all cope with any feelings of jealousy and insecurity?

I know that they aren't normal, I just want to know how is best to deal with them.

I was attracted by your username, similar to mine!

It's natural to feel strange about other people your partner has slept with. He is with you and not her so it cannot have been that good!

Determining between actions and thoughts may help. What has he done while you have been in a proper relationship together to make you feel reassured? Does he show others that you are in an exclusive relationship? Does he talk about past relationships? Does he know that it upsets you?

How does he feel about your past relationships? Does he feel secure with you? Would you treat him the way he treats you and vice versa?

If you had a daughter or sister and she told you the above, what would you recommend?