He lied to you from the off by telling you he'd split from his wife. What makes you think that is the only lie he's told you? Let's look at the possibilities:
Once she discovered he was cheating on her, his wife kicked his sorry arse out and, in time honoured fashion, he crawled home to his mum with his tail between his legs and, for all you know, you're just one of many 'other women' he's had over the years.
He visits his wife and family 3 times a week for cosy meals and chats. Sounds as if he's belatedly realised that you mean nothing to him and he's trying to convince his wife to take him back.
He's told you his children don't want to meet you. Why would they want to meet a woman who has caused them and their mother untold pain and heartache?
He's told you he doesn't want you to meet his children. Maybe he's told them - and his wife - that any relationship he had with you is over.
You know his wife would 'do anything to get him back'. Are you just guessing or is this another gem from his lips?
His ex has been a total thorn in our side Really? And what do think you've been to her?
Please understand that this man's wife is not his ex and that he has no intention of becoming your dp.
should I hold on in there There's nothing to hold on to except your dignity. Reclaim your pride and self-respect by giving this jerk the bum's rush before he dumps you.