Does fondling the penis without ejaculation, and without imagination, break the fast? And does unintentional ejaculation necessitate repentance?

Tampering with the private parts for the sake of lust is masturbation, which is forbidden in Islamic law, even if no semen is discharged, or without imagining images. One must repent from it. And while it is forbidden, it is also repulsive and has health harms. If no semen is discharged, it is not considered to break the fast.