Hi,
Glad to help

.
If Barbara and Lyle were married in Ontario, you likely won't find a record of their marriage. I assume (from Barbara's year of birth) that the marriage would have been in the 1930s or 1940s. These records are protected by Ontario privacy laws. It will be several years before marriage records from that time period will be public information.
However, you might find a reference to the marriage in a local newspaper. The local OGS branch or library may be able to help with that.
I see Lyle and Myron in the same cemetery as the rest of the family, so St. Mary's would be the first place to look for other records - and newspapers.
If you think members of your family may have lived elsewhere in Ontario, here is the list of OGS branches.
http://www.ogs.on.ca/branches/branchlocator.phpA quick google search will turn up library websites.
RK