What sort of documentation should I get from my boyfriend when I loan him money?

You should be very careful about this. As the saying goes, only lend money you are willing to lose. As for documentation, you may want a formal promissory note so there is no question about this being construed as a gift. If you really wanted to protect your interest, the loan could be secured by personal property under a security agreement in conjunction with the promissory note. In short, think long and hard about whether this makes sense.

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