Will I ever get over my ex?

I have two children from a long term relationship, we drifted apart about 6 years ago, but remained good friends for the sake of our children. A year after we parted he was killed in an accident so I was left to raise our children by myself with the help of close friends and family. I was single for about two years afterwards, concentrating on the welfare of my kids. But then I met a man online. We met a month later and there was an instant attraction betwen us and we started having a long distant relationship as we lived at opposite ends of the country. 6 months later we were moving to be with him. He had a child from a previous relationship so we made the decision for me and the children to move to his area as we thought it easier so he could be near to his child and we could be a family. I loved everything about this man, he was a great father, friend and partner. But things soon started to deteriorate. He suffered with very bad mood swings, jealousy, his sleep pattern and diet was very erratic because of his job. We didnt have very much money to spare as I’d have to move jobs and my house still didnt have any tenants. Unfortunately I only lasted 9 months before the mood swings got so bad I decided to leave after many attempts to make it work. Afterwards discovering he suffered from depression because of financial issues that I knew nothing about. We talked and he decided that he would make the effort to move to my end of the country, but being a completely different way of life and leaving his child, it wasn’t really an option and I couldnt up root the kids again so we decided to go our seperate ways and we havent spoken since. I now have a wonderful partner and although we’ve not been together that long we’ve just found out I’m pregnant. We’ve decided to keep the baby. We have a great relationship. The problem is I still have days where I really miss my ex. I love my boyfriend and know that we are going to be together till death do us part, but I don’t feel the intensity that I had for my ex. He took my breath away, but I wouldnt swap what I have now for the world. Is this something that I am just going to have to learn to live with. Will it ease as time passes. I find this is harder than dealing with the loss of my childrens father as this seems to be another type of grief, because you know they’re still out there living with someone else when it should have been you, that unfortunately circumstances wouldnt allow.. Can anybody help?