can my baby inside my tummy sense their dad from inside?

Wah not overthinking lah! My friend's gynae actually told her that by around 24-25 weeks, baby can already recognise familiar voices, especially ones they hear regularly. Someone in my mum WhatsApp group also shared that her baby would kick like crazy whenever her husband talked near her tummy, same thing! So even though you two broke up, baby still heard papa's voice enough to remember it, very sweet actually.

Yes, babies can actually recognise voices from inside the womb, and by 6 months they can hear quite well already. Your baby has been hearing his dad's voice since before the breakup, so it makes total sense the kicking picked up when he started talking.