Forgetting the Momo side (and I know Marten said it but still) will Dora class this as "Sven being a jerk to someone he hooks up with?"
It appears to be have been a no-strings attached deal, May is happy with that, but I feel that disregarding any triangle with Momo that somehow Sven will be the bad guy. Dude isn't allowed to have meaningful OR casual encounters, it would seem.
Sven needs to put Dora in her place. What he gets up to is really none of her business and she appears to be policing his love life despite her claims otherwise.