I just read your answer to someone that a marriage where the m’sader kiddushin was conservative/reform isn’t valid. First, I thought that a marriage can be valid without any m’sader kiddushin. But more to the point, I was married in a conservative synagogue in the USA. The rabbis were conservative. The aidim who signed the ketubah were conservative, and may or may not have been completely shomer shabbat. I’m now divorced and received a get. But if I was never married, perhaps I didn’t need a get? And perhaps I could marry a Cohen? Thanks for your reply.
The validity of a conservative marriage depends on the conditions of each ceremony. You are quite correct that the presence of a mesader kiddushin is not what validates the kiddushin. Kosher aidim are crucial. If there is a doubt a get is certainly required ,and the prohibition to marry a Cohen would be in effect. In general, if you had a kosher get I would advise you to consider the past marriage as valid, but for questions of conduct in the future you should consult a dayan about the specifics of your kiddushin.