I've been in similar shoes although with no kids involve from that awful ex of mine (thankfully)! I would honestly say to you to consider it all seriously since you have a child involved. It's never an easy decision to just 'walk away' when there is that much involved. Are there any close friends or perhaps a family member you can relate to in person? I found that for myself was helpful.

My ex told me exactly the same things but his actions unfortunately says the other. Afraid I'm probably in a same situation again with my current partner, it's never easy and I understand from your point of view.

Hope things will work out in a positive way for you!