if its what you really want to do, and your partner is ok with it, you could make a detailed contract between you and your partner, stating EXACTLY what will happen, what you intend to do, and what your partner's role in your suicide is (emotional support). include a final will as well as a note stating that your partner had no part in assisting you and that it was entirely of your own volition. then notarize it. this means you and your partner sign everything under the watch of a notary, who is an authorized, impartial witness to the signing of documents- its an anti fraud measurement that will help your partner out A LOT if hes taken to court or questioned by police (which he most likely will be). apparently you can notarize almost any document however i do not know what the process to actually find a notary is, so you will need to reasearch that on your own. obviously, the signatures are needed so that everything is legally binding. also make sure you add in an agreed amount of time that your partner will wait before contacting authorities. ex: he will wait 30 minutes from the time of your attempt to call anyone.
now, this is what i would do. but keep in mind im not a lawyer and i DO NOT know if this will actually work. you can try this, but in the end your partner may or may not recieve legal punishment anyway. he would have to take the risk. secondly, im basing this off my local laws. im not sure how things work in denmark, or if notarizing is even an option there. again, you would have to research this on your own.
i hope this helps! i really reccomend contacting a lawyer for some actual legal advice, but that can be pricey. its up to you, though. good luck <3