td;dr Some comments are saying Dante behaves like a teenager and that he is dumb and I think you all are not totally seeing what is behind his personality. First of all, yes, I do think having him go sleep in a church as a way of getting captured is not the best way this could have gone and there were many other, more creative, ways this could happen. However, you need to understand the life Dante has been living. When he was adopted, his parents showered him with love and affection and he felt safe and totally normal, but his parents were very religious, he probably didn't have many (if any) friends outside of church and then he died when he was a teenager. His parents abandoned him and he was tortured for a long time. Even after he escaped, he had already learned not to trust people and he was probably kind of scared of them. His life after that was lonely, he had minimal contact with other people and sometimes shitty interactions (like we see in the first chapter). He was living in isolation, "invisible" and "unnoticed". He has PTSD and was/is depressed from being alone and alive for so long. He is obsessed with dying. Living in community is how we grow and form our social personality, learn the queues of how to live in society. Dante had nothing of that. Mentally, he is still a teenager, he had no personal growth since he first died, except for learning to not trust people and fearing anything associated with churches, he doesn't know how to have a relationship with others. When he meets Demis, it is only with time that he starts to feel safe again, he realises how much he actually missed having someone by his side and starts to trust him, even though he doesn't want to. Demis grows on him, he likes spending time with him, and having a sexual relationship doesn't hurt ⁄(⁄ ⁄·⁄ω⁄·⁄ ⁄)⁄ . Also, the same thing happens to Demis (even though he mistakes it for ownership, Dante is his "toy"). He might not realise it, but Demis is probably also lonely, I mean, he is a murderer, he probably doesn't want many people around him, finding out his secrets... but he is not a sociopath nor a psychopath, he just likes what he likes (to each their own). On the day Dante first meets the priest, the priest doesn't force a conversation nor proximity, he is just nice and gives him lunch. So, even though Dante still has PTSD, because he is spending time with Demis and is starting to let his guard down around others, and because the priest was nice, he is telling himself that it is time to let go of the past, that this church is not related with the other and that the same thing is not going to happen again. He is making an effort to change his mentality, so when the priest ask him to deliver something to Demis, he goes with him. However, my friends, he is still mentally a teenager. Impulsive, reckless, stubborn, dumb, just like a teenager. He gets mad Demis stops spending time with him and goes to sleep as soon as he gets home, he doesn't like and gets jealous that it seems Demis and the priest have some sort of relationship, he storms out and runs away when he has a fight with Demis (that honestly only escalated because of Dante, Demis was just being his usual self). Him sleeping in the church is: 1. because there was literally no other place open for him to sleep and I don't know if you ever had to spend a night on the street, but it gets cold as hell, even in the summer, and is kind of scary to sleep on the street if you are alone; and 2. he goes downstairs because he is curious and dumb, and because he is so mad at Demis, it doesn't even cross his mind that he might be captured and tortured. That is all I want to say, this is only my opinion and, just like Demis, to each their own :)
td;dr
Some comments are saying Dante behaves like a teenager and that he is dumb and I think you all are not totally seeing what is behind his personality.
First of all, yes, I do think having him go sleep in a church as a way of getting captured is not the best way this could have gone and there were many other, more creative, ways this could happen. However, you need to understand the life Dante has been living.
When he was adopted, his parents showered him with love and affection and he felt safe and totally normal, but his parents were very religious, he probably didn't have many (if any) friends outside of church and then he died when he was a teenager. His parents abandoned him and he was tortured for a long time. Even after he escaped, he had already learned not to trust people and he was probably kind of scared of them.
His life after that was lonely, he had minimal contact with other people and sometimes shitty interactions (like we see in the first chapter). He was living in isolation, "invisible" and "unnoticed". He has PTSD and was/is depressed from being alone and alive for so long. He is obsessed with dying.
Living in community is how we grow and form our social personality, learn the queues of how to live in society. Dante had nothing of that. Mentally, he is still a teenager, he had no personal growth since he first died, except for learning to not trust people and fearing anything associated with churches, he doesn't know how to have a relationship with others. When he meets Demis, it is only with time that he starts to feel safe again, he realises how much he actually missed having someone by his side and starts to trust him, even though he doesn't want to. Demis grows on him, he likes spending time with him, and having a sexual relationship doesn't hurt ⁄(⁄ ⁄·⁄ω⁄·⁄ ⁄)⁄ . Also, the same thing happens to Demis (even though he mistakes it for ownership, Dante is his "toy"). He might not realise it, but Demis is probably also lonely, I mean, he is a murderer, he probably doesn't want many people around him, finding out his secrets... but he is not a sociopath nor a psychopath, he just likes what he likes (to each their own).
On the day Dante first meets the priest, the priest doesn't force a conversation nor proximity, he is just nice and gives him lunch. So, even though Dante still has PTSD, because he is spending time with Demis and is starting to let his guard down around others, and because the priest was nice, he is telling himself that it is time to let go of the past, that this church is not related with the other and that the same thing is not going to happen again. He is making an effort to change his mentality, so when the priest ask him to deliver something to Demis, he goes with him.
However, my friends, he is still mentally a teenager. Impulsive, reckless, stubborn, dumb, just like a teenager. He gets mad Demis stops spending time with him and goes to sleep as soon as he gets home, he doesn't like and gets jealous that it seems Demis and the priest have some sort of relationship, he storms out and runs away when he has a fight with Demis (that honestly only escalated because of Dante, Demis was just being his usual self). Him sleeping in the church is: 1. because there was literally no other place open for him to sleep and I don't know if you ever had to spend a night on the street, but it gets cold as hell, even in the summer, and is kind of scary to sleep on the street if you are alone; and 2. he goes downstairs because he is curious and dumb, and because he is so mad at Demis, it doesn't even cross his mind that he might be captured and tortured.
That is all I want to say, this is only my opinion and, just like Demis, to each their own :)