I'd heard remarriage rates were different for men vs. women after losing a partner to death so I googled it. (Assume instead of just his fiancée, we were talking wife just for the sake of argument.) According to a study in the Annals (take a moment to giggle) of Clinical Psychiatry: "Men are more likely to repartner after losing their spouse; more than 60% of men but less than 20% of women are involved in a new romance or remarried within just over two years of being widowed."
Of course they are, they need someone to take care of the kids. And no I am not just being flippant I've seen it happen several times (so therefore, is true).
As to our fictional friends.. possibly you wait longer if you're actually married like Wildman's husband. Janeway was only engaged which is basically saying it's not time to get married yet so it is a step down as far as commitment goes.
Were the crew declared dead?