Me and my partner have been on and off for the past 2 and half years now. We have an almost 1 year old son together and we are expecting our second child in 2020.

When I say we were on and off for the past 2 and half years I mean he left me for his ex girlfriend countless times, I caught him out in lies all the time messaging her and calling her and deleting messages etc. We split in May this year and I said I was done. I was fed up of feeling so low and insecure all the time.

However, we worked things out and got back together in June. He said he realised what he wanted and needed in his life and that he couldnt be without me and since then we haven't split up at all and things have been really good. he shows me messages from his ex (they have a child together) so I don't feel so insecure but I still can't help thinking all the time that something is going on or that he is lying to me. He swears blind to me that nothing is wrong and tells me that he's still here etc, he does try. He says I need to let go of the past and move forward but I am having such a hard time doing so that I make myself miserable on a daily basis.

I was never like this before..

He has another child to another woman also and I have absolutely no issues with him and her. They message all the time about their child and I never get insecure about that because I've never had a reason to.

I suppose my question is. How can I get over this? Or can I even get over it?

Or would it be better for his happiness and mine for us to not be together?

Sorry for the long post