... will my marriage be valid?
Different countries have different conditions for recognizing marriages concluded under foreign law. Generally they are recognized, though in some cases they might not be. For example, a country that does not allow first cousins to marry may or may not recognize a marriage between first cousins performed in another jurisdiction.
Nationality generally has nothing to do with any of this. The relevant conditions are generally things such as the age of the parties, parental consent if either party is underage, the family relationship between the parties (if any), and how any prior marriages (if any) have been terminated.
In fact, one does not generally marry "with" a nationality. If a marriage license or certificate lists the parties' nationality, that would be for the purpose of identifying the parties or perhaps for the purpose of recording compliance with immigration laws. But the marriage license and certificate apply to each person named, not to the person-as-a-citizen-of-a-particular-country. In most countries the process of having a foreign marriage recognized will be the same regardless of whether one or both of the parties holds that country's nationality (or the nationality of the country in which the marriage was performed, for that matter).
The Canadian government has a page on getting married abroad, which says in part
Marriages that are legally performed in a foreign country are usually valid in Canada, and you do not need to register them in Canada.
I was told from the London consular office (where I reside at the moment) that only a court can pronounce on the validity of a foreign marriage.
If the validity of your marriage is questioned, the question might end up before a court, but given the statement from the Canadian government that it is not necessary to register the marriage in Canada, you can assume that it would be very unlikely for that to happen. If you ever have to show your marriage certificate, you may want an authenticated copy (and, if the certificate is not in French or English, a certified translation). But for many purposes, all you will have to do is say that you are married.