Is this an emotional affair?

I made a new friendship and I'm genuinely unsure whether it should be considered an emotional affair or not - what's the line between emotional affair and new best friend?

I'm the ADHDer in my marriage. I don't make friends easily - to be more precise, I'm generally pretty good at being sociable with people (when social battery allows) but I really struggle to "convert people to friends" - a part of this is that I'll willingly socialise with people in pre-established contexts (work etc) but when it comes to actually asking people for their time, I always feel "not enough of a friend" to ask, or too much of a burden. So I mostly just socialise with people in various contexts and never really as "friends for the sake of friends". I have had friends over the years but they've mostly just fallen away as I've moved house, moved job etc, I find it hard to keep up with friends from previous contexts even if they meant a lot to me (this is all very ADHD/ND I realise - and knowing this kind of helps)

Anyway, this existence without close friends was the context in which my marriage existed for a long time, and it's hard. We've not been in a great place - we're still not in that good of a place, and when it's your whole social world the lows are especially low and the struggles with the effect of undiagnosed ADHD on our marriage wreacked havoc. We do love each other but, it got to the point where I'd just stopped trying - because it felt like effort just caused more arguments and that made them particularly hurt. I mostly just retreated into myself, played video games and took up a particularly bad habit as self medication (not how I understood it at the time, but looking back this makes sense) - I don't want to name the bad havbit but just for info it has nothing at all to do with infidelity (just clarifying because, that would colour this post a bit wouldn't it lol). In turn my partner did basically all the organising, all of the typical work a non ADHD spouse ends up forced to pick up, while getting little to no support from me. We were both pretty miserable. There were high points, but the overall tone was "this can't last" - and every so often I'd make a genuine attempt to change, but it only ended in frustration and me hiding away again

So anyway, last year I finally started taking my ADHD seriously again (long story there), part of the effect of which, was connecting with ADHD peer support groups, and my mind was blown when I suddenly started meeting people who actually understood how my brain works, because theirs does - and the shame. There are a bunch of people in these groups who I loosely consider friends, but there's one who I just hit it off with and we kind of both hyperfixated on each other as friends for a bit, to the point that now we consider each other best friends. There was a little while where my spouse was unaware of my new best friend, but it wasn't particularly long, and a lot of the reason for this wasn't that I considered it a "secret", more, my own social awkwardness made it really hard to talk about my new friend, particularly knowing the state our marriage was in. But I did have an absolute solid rule, that I was not going to meet 1:1 with this new friend (we actually knew each other at first via a facebook group) until i'd told my spouse about them. Making a new friend wasn't really something I'd intended to do and wasn't intending to keep it a secret, but IMO this would have crossed the line to inappropriate secrecy. So I told my spouse, and to this day I've never done anything with my friend that they didn't know about.

I'm confused and unsure because a lot of what the blog post on emotional affairs says, kind of sounds like my experience with my best friend. They're ridiculously easy to talk to and feel safe. I enjoy spending time with them and actively try to. I'd even say I love them but, in a way that feels like siblingship rather than romance or sexuality. They support me through hard times and I do the same back

But, the net effect on my marriage is I'm actually putting more effort in. I'm not running away from my spouse to spend time with my best friend. I've actually found it easier to keep the effort going rather than just give up and feel rubbish about myself, because I actually have friends now. I do make mistakes - occasionally I plan to do things with my best friend and leave it until the last moment to tell my spouse - but not because it's secret, because it feels hard to bring up. I'm an awkward person. My spouse doesn't suspect anything is going on that they don't know about (and there's not) but they do get jealous at how easily I get on with my best friend/the attention I give them despite the fact that I've genuinely been trying a lot more in our marriage too.

I don't know if this makes any sense. I've made the best friend I've made in years, the sort I think would have really helped in the early days of struggle in my marriage, and I really don't want to give that up