I'm new to this and new to this board, so here's my backstory:

I'm 25, a science grad student, have been an SD for nearly a decade and have a positive relationship with my SM. I'm a very active auntie to four nieces and nephews.

I've been involved with my guy, J__, for the better part of a year and it's quite serious. He has an eight year old son, A__, from a previous relationship. J__ and BM get along well, and A__ sharing/parenting is rarely an issue for them (it's not perfect, but it's not a spiteful relationship either)

J__ and I talked a LOT about my role with A__ when we first started seeing each other (in part because I haven't dated anyone with a child before and wasn't sure what to expect). The short version of our ~very~ lengthy conversations is:

His expectations of me are

a) that I'm nice to A__

b) that I respect his relationship with A__ and its importance in his life

My expectations of him are

a) that he takes me into account when making decisions about A__ and vice versa, treating both of us as important people in his life

b) that he let me and A__ take things at our own pace and feel our way around our new relationship without too much pressure from him

Our expectations of A__ are (remembering that he's eight, of course and can't be expected to act like an adult)

a) he is nice to me

b) is honest about how he feels about all of us

So far, we've all lived up to those expectations very well and I'm really enjoying having A__ in my life as part of having J__ in my life.

Here's where I have a couple of questions that I'd like ~constructive~ advice on:

1) A__ asks quite often when we're going to get married and tells me that he would like for me to be his stepmom. We usually just tell him that it's too early to know what the future holds for his dad and I, but that he'll be the first to know when we figure it out. This isn't working as effectively anymore (A__ is having some pretty major nuclear family cravings and, because he's eight, doesn't really understand "why it's taking sooooo long for you guys to figure out!?!" - haha)

Anyone have any experience or advice to offer in how to explain things to A__? I'm having a hard time with explaining that we're committed to each other, but not ready to get married. We're trying to find a way to get him off our case, without excluding him from the progress in our relationship, but also without transferring too much power into his corner. Yikes.

2) I've been very cautious to let A__ take all the "first steps" in my relationship with him. I've tried hard not to make sure that neither J__ nor I put pressure on him to get closer to me than he's comfortable with. So that means that I let him give me hugs and kisses first, I didn't stay over while he was there until he asked me to, I'm waiting to go to a soccer game until he asks me to be there, and so on.

Has anyone else taken that approach and have success or failure advice to offer on that front?

3) J__ was out of town recently for about two weeks, so I didn't see A__ for about two and a half weeks. J__ and I were talking the other night about his time out of town and I mentioned that I was pleasantly surprised to discover that I really missed A__. He was very surprised to hear that I missed A__, which really surprised me (I know, I know, it's a chain of surprises). His shock that I missed A__ bothered me all the next day, so I spoke to him about it. After a fair bit of chat, we sorted out that it just hadn't consciously occurred to him that I'd be attached to A__ and miss him when he's not around, not that I had ever indicated indifference or dislike towards A__.

Has anyone else had their partner express surprise that you've grown attached to their child and like the 'package deal'? Is this out of the ordinary?

As I said, I have lots of experience with kids (as an active auntie), and I have plenty of relationship experience, but I'm new to stepping and want constructive help.