I think I know what you're talking about are you talking about 뒷집 손님? At the same time, not sure since you mentioned the guy being blonde but ik the bottom is black haired and the first eps involves them fucking outside in the country side
Here's the link to the raws! ^^: https://newtoki319.com/webtoon/32512981?stx=%EB%92%B7%EC%A7%91+%EC%86%90%EB%8B%98&sst=as_update&sod=desc&toon=BL%2FGL&title=%EB%92%B7%EC%A7%91-%EC%86%90%EB%8B%98-1%ED%99%94&spage=1
Forgot to mention also english name: Back Door Guest
OMYGOSH THANK YOU SO MUCHHH I wasn't sure about the details but you actually figured it out thankieesss(づ￣ ³￣)づ
Pls help me find this manhwa, the top is blonde and bot has black hair. The blonde went in the countryside (?) i think where bot is living. They were fucking outside as well. Thats all that I can remember, its fairly new i believe