Keep spaces in code?

When I disable rich-text so I can add some html code such as a div, after I save my changes and then go back to edit them later, all the spacing has been removed.

So this;

 <div class="bluebackground">
 <div class="pagewidth">
 <div class="tabmy" id="tab1">
 <img alt="Homes" id="homes" src="/imagesmy/homes.jpg" />
 <h3><a href="homes">HOMES AND<br />
 RESIDENTIAL</a></h3>
 <div class="start">
<a href="homes">START</a>
</div>
</div>
<div class="tabmy"   id="tab2">
<img alt="Business Commercial" id="business_commercial" src="/imagesmy /business_commercial.jpg" /><h3><a href="commercial">
 BUSINESS AND<br />
 COMMERCIAL</a>

Becomes this:

<div class="bluebackground"><div class="pagewidth"><div class="tabmy" id="tab1"><img alt="Homes" id="homes" src="/imagesmy/homes.jpg" /><h3><a href="homes">HOMES AND<br />RESIDENTIAL</a></h3><div class="start"><a href="homes">START</a></div></div><div class="tabmy" id="tab2"><img alt="Business Commercial" id="business_commercial" src="/imagesmy/business_commercial.jpg" /><h3><a href="commercial">BUSINESS AND<br />
COMMERCIAL</a>

I cant fully show how the code should look as this forum removes indentation but I hope its clear what I mean. As Im in full html mode I would have thought that I could leave this 'formatting' in without it affecting the page.

Is this the case? If so, how do I preserve my code formatting?

Thanks