<prompt> Human: I am moving in with my boyfriend when my current lease ends in September. For context, weve been together since high school, and spent 3 years doing long distance due to my post-grad job. I finally got a job back in the same city last year, and opted to spend one more year living separately from him in the off-chance that things went downhill when I returned. He has owned his house for about 7 years, and I have been renting on my own for about 3. His mortgage is actually slightly lower than my current rent, and we dont have a massive income disparity, so we are planning to split the shared costs 5050. While we havent worked out all the kinks yet, our basic idea is that he will pay the mortgage, Ill cover utilities and other shared expenses, and whichever one pays less will transfer the balance to the other. We feel pretty confident about our plan at this point since we will both be benefiting financially in this arrangement. However, a few oddball questions have come to mind in the process:1. We are planning to be in this for the long haul, but I understand that sometimes bad shit happens. Should we have some type of rental agreement in writing since we arent married yet? If so, how should we go about getting that? Apologies if that is more of a question for rlegaladvice2. Will this have any effect on his taxes since I would technically be renting from him? For clarification, we are in the US.3. What do I do with my renters insurance policy? Do I cancel and just use his homeowners policy, or do I need to maintain my own separate policy?I know I am probably over-analyzing everything, but I havent been able to find solid answers online, and none of my friends are in this specific situation the unmarried couples are renting, and the others didnt buy their houses until they got married. Any advice is greatly welcomed!EDIT: Well I definitely didnt expect to get this many opinions! Im reading each and taking into consideration. I should have possibly clarified - this isnt a permanent live-in girlfriend situation. We are planning to marry within 1-2 years and will be saving to buy our dream house together in about 4-5. We just decided that it didnt make sense for us to try to sell his house and buy a new one just so that wed be equals. We are also both very logic-driven people, so I apologize if my wall of text doesnt convey the emotional side of the relationship. Trust me, if I was legitimately concerned about my future with my SO, I wouldnt be moving in with him. Thank you all for the advice!Assistant: Should we have some type of rental agreement in writing since we arent married yet? If so, how should we go about getting that? Apologies if that is more of a question for rlegaladvice1. While never a bad idea, if youre completely comfortable with the idea of not having any equity in the house if things go south, then I dont think its warranted. So if youre okay doing the 5050 split, and then walking away if need be without him giving you a chunk of money, its fine.2. Probably not. In the strictest sense, your boyfriend is getting rental income, but this can and is mitigated by your cost-sharing agreement. This comment addresses it in more detail. I cant say no, but... the IRS doesnt seem to make this an issue at all.3. Homeowner policy typically covers items in the house, but I would not be surprised if theres a clause for adult, non-owner, residents not having their personal effects covered. So just check with the policy.Human: Thank you for the information! I dont really mind the idea of not getting anything out of what Im paying, considering hed probably pay for any maintenance related things in the house. Also, Id guess that this situation is going to only last a year or so planning to get married within 2 years, so its not like Im going to be giving him a ton of money anyway. Also, considering the fact Ill be cutting my current rent in half, its not like Im getting screwed over or anything.  <response>: For context, I lived with my college sweetheart after graduation. He was employed and I went to grad school, plus he had a large inheritance from his parents. So, he got the mortgage and I paid the utilities bought groceries. Similar situation to you. We never bothered to work out if it was 5050 and pay the other back in all honesty I probably would have owed him.We ended up breaking up about 5 years later. It was amicable, and we both just walked away. There were no financial consequences, he never claimed me on his taxes or anything. Never had to deal with a break-in so I suppose I dont know how that works.I did always make a point of saying this is mine, this is yours and we did keep separate bank accounts, which I think was prudent. 