Do you think it is ever a good idea to get back with an ex?

For me no. Never a great idea to get back with an ex, they are an ex for a reason, whether by your choice or theirs. Not a good thing.

I dont think it is, unless you see tht they really have changed. My cousin broke up with some on cuz he cheated on her, in time she got back together. After a while he cheated on her again. :)

Hello!

Well, I would say that this really depends on a lot of factors. First of all you should consider why this person is not with you anymore. Is it because he cheated on you? Because you did? Because things didn't work between you to? Because you both made mistakes or just one of you did?

Relationships function both ways, if you're not together anymore there must be a reason and you might want to find that first to find out whether or not it might be worth trying again. Think about why it didn't work and see if you can find reasons it might work again.

Giving a second chance to someone is not inherently wrong, however sometimes we do it just because we miss that person in our life, or better, the idea we have of this person (which often doesn't match up with reality), or because we don't want to be alone. Sometimes though, trying again can make things work, if both of you are willing to commit and work for it, admitting your mistakes and forgiving each other. 

Once again, it depends on the situation and on what both of you are feeling. If he cheated on you, or treated you with disrespect, it probably wouldn't be a good idea.  One of the bases of a solid relationship is trust: If there's no trust, the relationship is going to be hard to manage and not desitned to last for long.

I hope you'll find a way to make things work one way or another. Best of luck!