Controller:
$partners = Partners::whereHas('partners', function ($query) use ($request) {
$query->where('partner_id', $id);
})->get();
Model partners:
public function partners()
{
return $this->belongsTo('App\PartnersPartners', 'id', 'user_id');
}
DB:
partners_partners
id - partner_id - user_id
(O ile dobrze zrozumiałem twoje pytanie)