Hi Kim
You both seem happy together and if he feels the same way about you it appears he’s moved on. Even though the child is young – indicating the split is recent – he is getting on with his new life with you. What would he gain by going back to a vindictive, bitter ex?
However, he has a responsibility for the child and will need to play a part in its life and you will inevitably get drawn in as you get closer. It wont be an easy ride, you will play piggy in the middle, mediator, peacemaker and the target of unpleasantness and jealousy from the ex. It can be hard to detach yourself but staying neutral is the best way, I went through a similar thing for 3 years and it can test the strongest relationship. His families interference and his spineless behaviour destroyed it but by supporting each other it will hopefully work! Take it easy for now, talk about problems/worries as they come up and see how it goes.
Hope it works out Kim, drop me a PM anytime if I can help
Lxx