"I thought about the "checked out" possibility too. But, if he doesn't care anymore why is he hiding it and why is he starting to come around being nicer to me? (Am I being too hopeful here?"

Good point and He may be noticing the Plan A - but might be struggling with turmoil.

Never too hopeful...Your DD is worth any struggle - she needs both active parents - its simple.

You are the mother of his child - he knows this and this might be what brings him over to your side of the fence.
How to "pull" him over is the trick.

Not all situations are cookie cutter. I have come to believe by reading here that exposure is the best tool in the arsenal. There are current sitches now in which the BS' are hesitate to exposed even when the S filed D.

It is action that gives the BS control over events and also puts the first cracks in an ongoing A. I am just not sure of the tactic in your situation.

If you have time - call that radio show tmrw. I am interested in what the Harley's say about this scenario.

W: 52
Married: 32 yrs
2 Sons (29 & 23)
1 Dtr (20)
1 GDtr (2.5) precious little girl