I've many holes but I will never leak ; Not comfortable? Just give me a tweak ; Though ............ What am I?

Question

I've many holes but I will never leak
Not comfortable? Just give me a tweak

Though often together most of the day
Come bedtime we'll go our separate ways

Life without me might be kind of a drag
'Cause when I'm not around things tend to sag

Doing my job, your reliable mate
This is a "hold-up" you'll appreciate

What am I?

Answer 1

A Belt

lines 1-2:
The holes are those in the belt for adjusting the circumference around one's waist according to one's comfort.

lines 3-4:
Normally, one wouldn't wear their trousers to bed and therefore also not their belt.

lines 5-6:
One's trousers may droop and potentially drag on the floor/ground without a belt.

lines 7-8:
The belt is a reliable "companion" which holds up one's trousers.

The title alludes to the function of a belt which is to hold up (or not let down) one's trousers.