I'm confused as well, where does the guy you are in a relationship with at the moment fit in your plans??? has he any idea about your contact with your ex??
As for soulmates the way your ex is carrying on he has no soul or any idea what he wants in his life, I wonder if you hadn't got in touch with him would he have got in touch with you ? I don't think he would !
Sorry to sound so harsh but when relationships go downhill and people split it's for a reason and very rarely does getting back together work because people grow and develop.
Neither of you are being fair to your current partners and you both need to move on leave your partners because it's obvious they are not right for you both.
I'm not sure how long you and your ex were together but it's time to move on and look to the future.
All the best.