Sigh. A Covington wedding, an Orussus divorce.
Part of me says there should be some limit to what you can do to a PC. Another part of me says there should be some limit to the expectations of a player who gets his character in a jam, then goes AWOL.
I'm trying to think of what part of this couldn't be undone relatively easily out of game. Bringing back a dead PC or NPC is problematic. Leaving a PC in a prison in some far off land while the rest of the party returns to Orussus is problematic. But, absent some elaborate writeup in the PC's background declaring his or her love for their childhood sweetheart, what harm does a crossbow wedding do?
If the player doesn't come back, then the PC and the PC's NPC spouse live more or less happily ever after. Roll versus marital bliss DC.
If the player does come back, then they can make arrangements to continue adventuring despite the fact they have a family, a la Rinaldo (our lvl 5 spice merchant!)
OR...the player can make arrangements to abandon their spouse, rather mercilessly. There might be some in-game complications to that...
OR...the player can seek whatever passes for a divorce in whatever region will allow it. Local laws may vary.
OR...the player can make arrangements for their spouse to become "missing". There would probably be an alignment check associated with that one, unless the character was already evil.
I just can't see where this is any more entangling or limits a player's options for a PC any more than, say, the PC making a powerful friend or enemy would do.