I live in the UK and my partner lives in Sweden. We want to find a prepaid travel card solution that means we can both top-up the same card from our separate countries (and bank accounts) and then use the same card to spend when we are together.
I’m not sure that any provider offers quite what you’re looking for. It sounds like you would like a joint account that both people can access, and that issues both people their own cards?
If so, most UK providers will require both account holders to be resident in the UK (and knowing Swedish rules it would be even harder for one to open a Swedish joint account with one of the account holders not being in Sweden).
I definitely don’t think Monzo would be ideal as to hold an account, you need to be a UK resident, and you can’t just open a joint account without having a personal account first.
If you just want to have one card, that one of you keeps, and you only use the one card for ‘together’ spending, something like Revolut might be useful. It can be topped by by a debit card from any country.