Under common law, she is entitled to being compensated for having spent money in reliance of the promise made to her. Even in a written contract, one does not need to set out the consequence clause to obtain settlement or compensation for money spent based on a contract having been entered into - see the analogy provided above of the business man and chef. The guy did not need to say I’ll pay you back if I don’t marry you or have witnesses to such an agreement. The agreement that needs to be proven is the engagement - which no one is calling into question. The legal principle is called detrimental reliance.
**Does common law apply here? Did they live long enough where common law applies? Is she pregnant? Etc.?
Even if that applies, he may be responsible of half of expenses at most. There are examples where even court could not make the guy pay the expenses.**
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(Was he already married? Just to add to list of any material evidence in her favor like I mentioned in my post #29 and #31)**
http://howdoigetmyexboyfriendback.org/9418/broken-engagement-whose-responsibility-are-wedding-expenses/**
Your analogy of chef and restaurant owner does not apply and you yourself said:
**“In the engagement situation - obviously there is no written contract - it’s not a conventional in that relationship.” 
The courts cannot compel the guy to marry the girl, what they can do is undo the monetary damage caused as a result of the actions of the guy.
What action? Backing out? He is free to do that and she was free to spend. Unless he promised to pay the expenses he is not legally bound. Morally and ethically yes, but not legally as far as we see here.
Kyun kai aap khud hi kehtai hai:
Auron ko bhi to yeh mauqa dayna chahiyay, kai woh bhi aap kai intelligence sai impress ho jayein. Jab koi aisay topic pai tapsira kartha hai kai jis mai us ka kam ilm ya maalumaat ho, to woh kisi ko impress karnay kay position mai nahin hota hai - kabhi kabhi khaamosh rehna ya munasib sawaal poochna hi kisi ki zahaniyat ka suboot dayta hai
You can see I am giving you full chance to do that.