If you want a direct merchant account instead of an aggregate solution like Verotel, the acquirer will need to know exactly what you're doing. If it's just a dating service where people connect with each other, I would refrain from using the word "adult" since that implies explicit content or explicit services.
Assuming you are processing upwards of 100,000 EUR/month or a million SEK/month, you might be able to get Adyen interested. For lower volume, SecurionPay might be able to help you out. Not sure if SecurionPay can do SEK but Adyen can.