It's clear that your son has a very deep longing for a father figure in his life. But I agree, this is way too soon, and maybe the timing will never be right. Just because someone is your partner, doesn't mean they want to be your sons father.
But, how does your 7-year old son know your partner of only 1 month?
Did you introduce a partner you've only been with for 1 month to your child? If that's the case, no wonder your son is confused.
Your son will not know healthy boundaries and timelines unless you respect them yourself, so you can teach them to him. Bringing new relationships to your son, especially since he doesn't have a father figure and is looking for a male attachment figure, is quite selfish and doesn't take into account what's best for your son.
My advice would be to slow down. Slow down how intensely you're diving into this new relationship, so you can help your son slow down.
A conversation about this should be between you and your son, not you, your boyfriend and your son. Your boyfriend is not a parental figure and has no business parenting your child. Otherwise you're sending mixed messages.
So you sit your son down and you explain that getting to know someone and deciding whether you want this person to be an important part of your life takes time, a lot of time. And that right now is no time to be making decisions. Just like you can't decide whether this boyfriend is going to be a permanent part of your life, your son shouldn't rush to make this a permanent thing either.
Calling someone dad shouldn't be taken lightly. It's an important name that holds a lot of value, and it shouldn't be given. It should be earned. Tell your son that someone needs to earn that place in his life by consistently showing up for him, day in and day our, year in and year out, before someone can earn such a special place in his life.
I would advise against making your boyfriend a very active person in your sons life for at least another year. First figure out whether this relationship has any standing, then try to see what role your boyfriend will be taking up in your sons life. Not the other way around.