He didn’t realise me waiting like this was hurting me so much.
He's either thick or a liar. Spoiler alert - he's a liar and he thinks you are thick.
He told me this morning again that they are merely co-habiting and I have to trust him.
If that's the case why can't he be openly in a relationship with you but live with her? Why can't she know? Because he's made you the OW, that's why. And though he did so sneakily at first, you now know full well you're a secret but have stuck around.
He has sworn he is moving out again imminently
What date did he give you then? What specific date did he give you, the woman he desperately wants to be with properly, for him moving out?
and if had known that me waiting for him would risk losing us he wouldn’t have asked me to wait so long. We will see.
He's told you outright how fucking arrogant he is. He didn't realise that him expecting a woman to wait FIVE YEARS for him would potentially mean he lost her?! He really thinks a lot of himself doesn't he
We will see.
You'll just keep waiting and waste even more years, if that conversation is wasn't enough for you to walk away.
He's lying to two women but at least you know he's lying to you. She has no idea.
Sorry but you need to grow up, bin him off, get yourself together, focus on your own mental health to stop this ever happening again and move on with your life.