Send All MultiSelect Listbox Choices To Sheet

i have this code to populate the worksheet from listbox selections, but it only works on a 'one at a time' basis.

Private sub cb1_click()
Dim i As Integer
Dim Ltm As String

With ListBox1
For i = 0 To .ListCount - 1
If .Selected(i) = True Then
If Ltm = "" Then
Ltm = .List(i)
Else
Ltm = Ltm & ", " & .List(i)
End If
End If
Next i
End With

With ActiveSheet
.Range("B" & .Rows.Count).End(xlUp). _
Offset(1, 0).Value = Ltm
End With
For i = 0 To ListBox1.ListCount - 1
ListBox1.Selected(i) = False
Next

what i am trying to do is once i have checked several items in the listbox is have all of the checked choices fill iin column B at once.