@Seasnail- the biggest thing, which you will hear a lot, is communication. You should communicate your desire to know these things versus trying to guess whether or not you should ask and when it is appropriate to do so. Everything should be discussed and clear to your both (i.e. the nature of your relationships, possible future of your relationship, expectations of the relationship, desires involving interaction with other people, and comfort levels of sharing those interactions in part or in-depth). That's the only way you will know how to proceed in your own life and additional relationships. Though, you two have agreed to just go with the slow flow, it doesn't hurt to have a casual conversation about the above-mentioned things.
Hope it all goes well.