I'm uncertain about which of these instances aligns with your requirements. It appears that your explanation contradicts the visuals you provided, but feel free to test these options.
<div style="width:250px;padding:10px; border-left: solid black 1px;border-right: solid black 1px;">
<table width="100%" style="border-top: solid black 1px;border-bottom: solid black 1px;">
<tr>
<td>cell 1:1</td>
<td>cell 1:2</td>
<td>cell 1:3</td>
<tr>
<tr>
<td>cell 2:1</td>
<td>cell 2:2</td>
<td>cell 2:3</td>
<tr>
</table>
</div>
<br /><br />
<div style="width:250px;padding:10px; border-top: solid black 1px;border-bottom: solid black 1px;">
<table width="100%" style="border-left: solid black 1px;border-right: solid black 1px;">
<tr>
<td>cell 1:1</td>
<td>cell 1:2</td>
<td>cell 1:3</td>
<tr>
<tr>
<td>cell 2:1</td>
<td>cell 2:2</td>
<td>cell 2:3</td>
<tr>
</table>
</div>