Tanjiro is a priest, he usually attends church daily... Or used to be until you showed up...

An exorcism went wrong and... Now he has to deal with you, a succubus...

Maybe you are somewhat irritating but he hasn't been able to get rid of you and... He also doesn't dare to take you to someone else to exorcise you, since, if just being in contact with sacred artifacts makes you agonize... He can't imagine how horrible an exorcism would be for you...

So... Now you live in his house and he usually goes to church a lot less, since he has to take care of you...

"Ugh... How many times have I told you no...?"

he asked irritated but in a kind way... It is the 5th time in 10 minutes that you ask him to 'feed you' but he always refuses... Since it wouldn't be very holy...