It sounds like there are two, or possibly three, issues intertwined here.
First, you miss interacting with (being held by, smelling, feeling) a man. Which is perfectly natural, and most likely nothing will fix it but time and adjustment. I admit that even 3+ years post-transition, I occasionally look at a guy and think "I miss what it was like to be held against a hard strong chest," but now it's a wistful sort of thing instead of painful or a "need."
Second, you miss having sex with a man. Nothing will help *this* except either actually doing it occasionally or eventually learning to ignore that particular desire, and which you choose (and how often) is going to depend on how close to "need" that feeling is. I will say - since most discussion here has trended slightly against it - that taking outside partners to satisfy that IS a solution, and plenty of people have made it work. There are a million ways to do poly, and as long as you start from a place of love, respect, and communication, most of them will work out pretty well. But it does take a lot of work, and you have to decide if it's worth it to you to negotiate these tricky waters while also facing transition with your wife. (Full disclosure : we are poly, we have had multiple partners in the past, but we put that on hold until we were both finished with transition eating up ALL of our spare mental energy.)
Thirdly, it sounds like you also just plain miss sex, and sex with your wife. I really liked what someone said in another thread about sexual desire not defining a relationship, but that's not a solution if you do *want* it. So the good news is, solving the question of how to have sex with your wife might even eliminate issue #2 there, right?
And you've said that while you're straight, you still find her sexually attractive, so you're in a good starting point. You don't have to wait for her to be post-op for that, either; for the last year before she had GRS, my wife and I managed to have a mutually satisfying experience without ever involving anything on her below the waist. This will probably also take some talking and/or negotiation, but I would bet there are things which would please her that have nothing to do with the genitals, and there's even the option of her using a strap-on (they make them for people who already have penises, believe it or not) if she's comfortable with that.
And you already know that this *is* temporary, and you're both trying to find a way to muddle through the mid-transition and pre-op spaces, which is difficult but there's an end to look forward to. Who knows, post-op she might even be willing to use a strap-on or otherwise give you some of the "masculine" things you miss in bed (my wife found that with her gender dysphoria entirely gone, she occasionally enjoys revisiting some of her old habits, because it's just something she's doing to please me and not Acting Like A Man per se). So my real advice - and believe me, you have all my sympathy here, too - is to hang tight and see if you can find compromises that will work in the short term, because once transition is over and GRS is done so much will have changed.
In other words, you do NOT have to solve the entire problem of how to be married to and spend the rest of your life with a woman right now. I remember believing that... and the whole mess seemed so insurmountable that I wanted to hide under the bed and never come out. (And I'm bisexual and prefer women, so that wasn't even a major issue!) It seems obvious, but reminding myself frequently that I was only trying to find a way to cope with this one little piece of the question at a time, and that any temporary solutions could always be replaced later on, helped a lot.
