Having proof that you contributed monetarily to the household might be remotely helpful. But, in the absence of a provable contract addressing monetary reimbursement should you split up (like a pre-nup for married people) you contributions may still be considered gifts.
My guess is that there was never even any talk of reimbursement while the relationship was going well, so you can't even prove a verbal agreement.
Now for the "legal" stuff:
https://en.wikipedia.org/wiki/Palimo...s#cite_note-98
For further "legal" information read Brooks v. Kunz which involved (among other things) property held by both parties by deed. Is spite of deeded ownership the court remanded the case back to the trial court to seek evidence of the contribution of Brooks.
https://scholar.google.com/scholar?h...palimony&btnG=
Once you have read that, read the 27 subsequent cases that cite Brooks and see if the decisions of those cases help you any.