Create columns of equal width that span multiple rows by inserting a .w-100 where you want the columns to split on a new line.
<div class="container">
<div class="row">
<div class="col">col</div>
<div class="col">col</div>
<div class="w-100"></div>
<div class="col">col</div>
<div class="col">col</div>
</div>
</div>
