My 2 cents here...
IMO Lisa dropped the ball BIG TIME because:
1. She promised him to have kids knowing that's what he wanted more than anything and she went back that promise.
2. She said all she could see was the custody battle in the future, thus subconsciously saying that she knew they wouldn't last (which was also very important to Michael).
3. When Michael said to her that if she doesn't want to have his baby, Debbie will, she with her sarcastic behind told him to go ahead.
She really thought Michael was a big ball of mush/pushover and couldn't stand up to her or stand his ground about things. No doubt he loved her yes, but he wasn't going to let her come in and dictate his life on her grounds. He could be as firm as a 100 year old tree and stubborn as a mule when he wanted to be.
I think as far as Michael is concerned:
1. He felt utterly betrayed by her flip flopping on him.
2. He was sick of waiting and wanted babies...like yesterday.
3. He could see by her "custody battle" fears that she wasn't as committed as he'd hoped and she did not hold a future vision of them together (so in effect what did he have to lose if she was calling it on their future already?).
I do believe they loved each other very much and from what little I know I believe he had his greatest romantic connection with her out of all the women in his life. That said, even if Michael hadn't had the kids with Debbie I don't know if his relationship with Lisa would have worked out because it seems that Lisa only felt/knew certain things about Michael AFTER the fact.
She couldn't fathom that he could be a good father till AFTER Price was born and she wouldn't admit to herself and others how much she truly loved him until AFTER he was dead.
Too little too late.
One more thing....Lisa Marie isn't a strong person. She just pretends to be. It's her facade. She acts like a rebel without a cause when it comes to her mother, but believe me....check behind the scenes and you'll see that Lisa cares very much about what her mother has to say and always has. When she was taking stabs at her mom over the years, it's just her trying to get a rise out of her, just like a rebellious teen would do.
I wouldn't be surprised if 90% of her "feelings" about Michael after the break up was just her channeling her mom.