How long does it take for a guy to finally ask you out and make this official?

I'm in no rush or expect this man to ask me to be his girlfriend anytime soon. But it's been a while since I have started seeing someone new. It's been 4 years. I was married but currently separated and I have been seeing someone else. But I'm wondering, how long (given the fact that this guy I'm seeing makes an effort, in which I got kind of lucky to have landed someone so nice and gentleman like) it's been four months since we have been hanging out and talking. So I just wondered what is the average wait time I should give this until we are both ready to say we want a relationship because he has told me that he really likes me and that at first we both agreed it to be casual but so far we've both realized we truly like each other. It's so much more than sex, I mean the sex is great but we also can have conversations etc talk about things. So as I said I'm not in a rush to get into a relationship. He isn't seeing anyone apart from me and I'm only seeing me. Also he did confess and told me in the very beginning he was seeing other girls but decided to stop because he ended up liking me more.. so I guess that says a lot. I just want to know your opinion about how long it would take for him to ask me to be his girlfriend. Thanks !
How long does it take for a guy to finally ask you out and make this official?
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