As you've made your bed, you'll just have to lie in it.

[impeccableman]

A friend of mine have done something that he regrets, I want him not to think over it again and again and I want him to understand he could not travel back time and he'll just have to accept the situation.

Q1:Can I say to him "As you 've made your bed, you'll just have to lie in it."?
Q2: Does this carry negative connotation like "you deserve it"?
Q3:Or, the meaning of "As you 've made your bed, you'll just have to lie in it." depends on the context ?

[Marius Hancu]

>Does this carry negative connotation like "you deserve it"?

Yes

Perhaps:

That's life. Carry on and don't look back.

[OddThomas]

The pigeons have come home to roost also has a negative implication.

Don't cry over spilt milk suggests a little bit of fault, or some accident.

But That's water under the bridge, and That's water over the dam, are fairly free of negative connotations. Don't mix them up! Mind which way the water goes. :)

(BTW, you're wise to know that no decision today can change the past. This truth escapes many people.)