Well, that is quite a niche question! While I obviously can't know the exact history of Jens Nielsen, I'd wager that the short answer is no. At least, not very likely.

You see, as a protestant nation, the laws of the time, especially concerning marriage and sexualty, were based on the bible, in this case the 6th commandment. It would be illegal for this good old Jens Nielsen to have more than one wife - at a time. It could be possible, though unlikely, that he married 6 different women through his life. If you're interested in the sexual mores and laws of the time, Nina Kofoed is quite a good historian who have written quite a bit about it - I can recommend you a book or a couple of articles if you want. All in danish though - but I expect that won't be a problem for you?