I (33M) have been dating a woman (31F) who wants to be in a non-monogamous or poly relationship, but she currently has no serious partner. I explained that I haven't really had any relationship experience before, monogamous or polyamorous; my default mindset has been towards monogamy, but I told her I am open to the idea of non-monogamy or polyamory.

She has had several previous relationships, but she is relatively new to the poly lifestyle herself and has only had several casual relationships over the last few months since her last relationship ended, which was monogamous and it ended because she wanted to open up the relationship and he didn't.

We haven’t detailed the specifics of what being non-monogamous entails beyond casual dating, but I am at a point where I would like to broach the subject of being in a relationship. We've had three lengthy (6 hour each) dates over three weeks, and we've talked so much it feels like we've known each other for much longer than that. I've never met someone who I felt was immediately so accepting of me exactly as I am, and we have a lot in common, so I feel like we have a really strong connection.

We had sex on the second date; we talked about STDs first, and we both offered to show each other test results showing that we were negative, but we took each other's words for it. She also talked about birth control, and she told me she was on it, so after the discussion about STDs and birth control, we had unprotected sex. She told me that I was the first person with whom she hadn't used protection outside of her previous monogamous relationships, and she was the first person for me as well.

We have tentative plans to get together again sometime in the next week or so, for me to take her out for her birthday dinner, at which point we will have been dating for about a month, so I might take the opportunity to try and clarify our relationship and ask how she feels about being in a defined relationship of some kind. I would like to suggest being her boyfriend or her "main partner," with other partners being more secondary in the hierarchy, if that makes sense or is even possible.

I would also like to try and establish that we agree always to use protection with any other secondary sexual partners outside our relationship, so that it's not only safer for everyone but so that there is still a certain aspect of exclusivity between the two of us.

I think, for me, if she and I agree to be each other's primary partner and agree to forego protection only when we're with each other, that's the most realistic way I can see an ENM or poly relationship working out. Given my general inexperience with relationships, I don't know if it's too soon to have this conversation, and I don't know how to approach it.

How does being in an open relationship or an ENM relationship or poly relationship differ in any way from what we're doing now, dating non-exclusively? What are the typical parameters of an ENM or poly relationship?

I would personally like to feel that we are each other's main emotional and sexual partners; I don't want either of us to feel relegated or like we're playing second fiddle to anyone else, but I don't know how poly people typically go about defining these roles in their relationships.

I tried to ask for advice on r/dating_advice but most of the responses were essentially saying that the relationship was doomed, I need therapy, that I must have low self-esteem for considering such a relationship, that I would be emasculating myself, etc., so I'm hoping for maybe a bit more support than I got there.

I would appreciate any constructive advice on how to navigate these discussions or manage the complexities of this kind of relationship, especially as someone very new to the concept of polyamory. I'm not entirely sure whether it's right for me, but I'm keeping an open mind.

Tl; dr: I've been dating a woman who wants to be in an ENM or poly relationship; I'm open to it, but I am totally new to the concept and I need advice on how to go from just dating to being in a relationship. Are we boyfriend/girlfriend if we're not exclusive? Are we primary partners? I need help figuring everything out.