Update!

So today I ignored her phone calls for 2 hours, then I finally called her.

Interesting talk, for 40 minutes - the longest ever. I dropped the hint that I suspect the guy was over - but in a very subtle manner - the worst thing you can do is appear jealous over the phone. She said of course not - and if he comes by to see his kid, she told me she'd tell me.

She is having room mate problems, told me about them for the bulk of those 40 minutes. They are not very responsible, and leave her to fend for her self.

I wonder if that 40 minute talk was to defer my initial suspicions about the ex being over. Hm, I wonder!