Holly Madison Reveals Why New Boyfriend Hasn't Met Her Kids

Holly Madison is taking things slow with her new boyfriend, Steve Dimopoulos ... and it's going to take him a long time to meet her kids ... if history's any indication.

Holly joined us on "The TMZ Podcast" and told us her joint custody arrangement keeps her life pretty compartmentalized ... half the time she's with her kids, and the other half is when she focuses on dating.

That setup has led Holly to be incredibly cautious about introducing romantic partners to her kids ... she revealed her previous boyfriend of six years, Zak Bagans, never even met them.

Holly says when she was with Zak, her kids were still little, and she wasn't looking to shake things up after her divorce from Pasquale Rotella. Looking back, she says she may have had a subconscious feeling about Zak ... which could explain why she never felt the need to make the introduction.

As for Steve ... Holly isn't putting a specific timeline on things. She says she wouldn't necessarily wait six years again ... stressing it's more about the right person, the right timing and what feels natural.

Holly also touched on her relationship with former 'Girls Next Door' co-star Kendra Wilkinson ... it's been a while since they last spoke, but it sounds like there's no bad blood.