For one thing I would never ever buy a big ticket item like a car or house with a girlfriend no matter how long we are together unless you have the legal stuff worked out very specific like in the case you should break up down the road. Something like this can ruin your life for sure. It's your call. You know what your relationship is with her and Randy has some good advice there.

Welp, usually when you hear only one side of a story...that's exactly what you get. Second, nothing is all them or all you. Never...no how. Third, YOU have to decide what's best for you. We can't even begin to do that.

Go into the bathroom...look in the mirror...and find out who you really are...if you've got the stomach for it. Then ACT!

And quit relying on nitwits like us to solve your self induced problems.

yorolpal

And quit relying on nitwits like us to solve your self induced problems.

Yar!

Thanks Guys - it's a very complicated situation - much more complicated than one would think, but I did go for a 45 minute drive today to look at a place of mine own to rent.

You do realize that this is not an issue with your partner's mother? Your wife wanted to buy a house and move, and you were in no hurry to do so. She did not address the issue with you. She went and looked for a house with a person she could expect to support her decision, decided to buy it without consulting you, and presented you with a fait accompli. Her mother was at best her confidant and at worst her accomplice. Why would you imagine your mother in law would show you any consideration if your wife does not? 

It is rare that a trashy rap song is appropriate as an answer, but this may be an exception.  i don't understand half of what he is saying , but the chorus works for this situation:
warning, foul language..i think
http://www.youtube.com/watch?v=M37HHf099oM
 
Anyway, no good can come of this situation.  Walk away while you still have sanity.  This situation is downright disrespectful to you. She is being the female equivalent of a "momma's boy".
 
 

You've gotten some excellent advice IMHO from quite a few posts above this one.
 
Your girlfriend.... not wife.... more like a shack up friend with benefits... with whom you have lived for 5 years..... apparently and obviously, trusts and confides more in her mother than she does in you. That's a HUGE danger sign to the future of that relationship. HUGE.. The fact that she didn't include you in decisions like this or tell you of her plans speaks volumes as to what she thinks about you and where she places your value to her. Not very high on her list of priorities.
 
Regarding the new house.... if she has signed the papers, she's legally committed to it. Since you're not married, unless you too have signed the papers, you are not committed to the deal.  Before you sign or move in, you better have a serious self evaluation and a long hard discussion on topics that matter with your girlfriend.
 
Depending on the state you are in.... state laws vary on the length of time required for a shack-up to be considered a legally binding (in a court of law) common law marriage. My understanding is that most are 7 to 10 years or continuous co-habitation. At that point, she has the rights of being married.... alimony,  share of family assets and all those things lawyers and judges get to decide who owns on termination of the "marriage"....
 
I've been married one time.... and we're still married. It's been 33 years. We had this discussion early in our marriage about the in-laws and just how much they should be allowed to influence our decisions. I married her, not her parents, and she married me, not my parents..... with that resolved early on, and by kindly informing the in-laws on both sides when they first poked their noses into our business..... life has been good since everyone knew their boundaries early on. My wife and I have an excellent relationship with her mom.... she's the last one still alive from our in-laws.... and I don't begrudge her time together shopping or whatever..... but we, my wife and I make our decisions together and discuss things of importance at length before we decide, TOGETHER.
 
If you're not working together, you're moving apart.
 
Being musicians..... I wrote this song about things I saw happening in the lives of others.... my friends, my wife's friends, through the years...  
 
http://soundclick.com/share.cfm?id=12024980
 
I can't and won't tell you what to do.... only you can decide the best road forward for you...and her.

for those who are saying that a live-in girlfriend and wife are not the same, that's not necessarily true.  in some states in the US (Texas being one of them), there is a common law marriage which is very legal and binding.  it takes very little to prove cohabitation and any form of cohabitation in Texas means the couple are "common law married."
 
Texas has NO time limit on common law marriages.  a couple only has to be living together "as husband and wife"
 
common law marriage has the same weight in Texas as a regular marriage performed by a judge or pastor. 
 
and anyone married in texas, by common law or by license, does not have to have the partner's permission to buy big ticket items without the partner's signature, and yet that partner is still responsible for 1/2 ownership of said items.
 
for example, when I first moved to TX, I bought a house.  My wife was not in town during the transaction of the purchase of this house and her signature was not on any legal document for the purchase of the house.  however, she is legally responsible for paying for the house in TX since she is my wife.  and if we were to divorce, the judge would determine that 1/2 of our debts and 1/2 or our assets were to be split between us, including the house that she didn't buy.  (oversimplified, I'm sure and I'm not a lawyer).
 
so if this couple were in TX or another "common law" state, then they are already legally married and she might have the ability to purchase a house for both of them without his signatures.  it IS possible in some states.
 
 
having said that, depending on the state he lives in, the OP might need a lawyer to get out of this.

That's why I originally posted "I don't know about the common-law" but all provinces and territories within Canada, excluding Quebec, follow the common law legal tradition that seems to vary within Canada...and I'm guessing he's near something in Canada.
 
 
I think the issue is, where applicable is; you cannot get out of a common-law marriage as easily as you can get into one.

spacey
 
 
I think the issue is, where applicable is; you cannot get out of a common-law marriage as easily as you can get into one.

'xactly!