You never met his wife before?
Tapping it is all about whether you want him to stay friends after you hit it. You just into hitting it and then movin on or they close enough locaiton wise where you can have regular fun? You prob just gotta figure out a few things.
Does your friend know you get with married women and if so does he have any take on it. Some dudes are cool with u fuckin mwfs as long as it's not theirs and others get into the idea if you can give them an idea of what it's about. The main thing is if he knows you get other mwfs, what's his deal and is he possibly cool with u tryin it out with him and his wife. But from my experience, most hubs don't just jump into that after hearing about it, takes months usually before they get more into the idea. And this guy being a newlywed, I doubt he'd get into that idea in the first few months/year of being married though.
Next thing is the most important but is his wife even into you? Or you think you can get her into you? If not, none of this matters right?
With most of these married couples, you're not going for any sort of "seduction" angle, the mwf in most situations is the one that is making it happen. She knows what she wants and she'll put the signals out so both you and the hub knows what's up. Not like saying these mwfs are blatnatly obvious, just saying that with all the chatting how hubs can do this, and how we bulls do that and can do this, with most real married couples, especially if the wife is hot, it's all on her. You can work it, hit on her, etc but until she green lights it within herself you're spinning ur wheels. if she is into you, chances are the hub could eventually be into the idea cause she'd be workin him over the months (years).
So, first understand where your bud is coming from in terms of this lifestyle and then also see what her take on you is.