Based on your financial expertise, provide your response or viewpoint on the given financial question or topic. The response format is open.

How can I legally and efficiently help my girlfriend build equity by helping with a mortgage?
A 30-yr mortgage IS a committment. So, you are willing to commit to a place, but not your long-term girlfriend??? Either you don't do this "cheap" scheme idea, or you set up as a business arrangement, or you get married. This is quite a laissez-faire statement you make... "Maybe we will eventually get married, maybe we will eventually break up, who knows." Anything or anyone that is a "who knows" is not what you make a 30-yr committment on. I mean, unless you just want to risk throwing your money away. Now, man up, hire the lawyer to do official paperwork or else get a legal certificate of civil union or marriage or whatever you want to call it. If you try to do your cockamamie scheme "on the cheap" now, it will most surely cost you dearly in the future! Mixing money (particulary huge sums of 200,000 $!) when there is no legal obligation like marriage or a business contract, is a fool's errand! Now, grow up and do it the right way if you want to help her - and yourself too.