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>