I want my ex back and to understand why we broke up

You are going to have to provide a lot more information than just that.

Try to read the other threads in this forum to see if that helps you understand things better.

How did the breakup take place?

So call him up on the phone and ask him why, and beg him to take you back ?

Is he dating someone else already?

i want my ex back and to understand why we broke up

To what end?

The word ex says it all.

People don't break up with other people just because they're bored. There's a reason he/she left, but he/she doesn't owe you an explanation. It could be as simple as feeling that the relationship wasn't going anywhere.

It really is best for you to stop tormenting yourself over this and move on. Most times an ex remains an ex and you will never truly know why.

For your own well being, move on and find someone else.

Why do you want him back? And why do you need to understand why it ended?