Three things stand out for us at the moment.
The first is our adoption of daily choices. By this, I mean each day's affectionate activity 'belongs' to one or other of us. Taking it in turns, we decide and initiate what we would like to do, when, and for how long. This could mean passionate sex in the afternoon, or a slow cuddle in the evening. The important part is that neither one of us has a monopoly over deciding, and initiating, what we do. This has been extraordinarily helpful.
Secondly, our intention to avoid orgasm, even when lovemaking includes the sort of stimulation that would ordinarily lead to it. This encourages a completely different approach to sex. It doesn't seem to matter if orgasm then happens, because it will have been preceded by something equally as, if not more, valuable. The key is that our intention to avoid orgasm has to be genuine, at least at the outset. If that intention is later blown away by passion, so be it.
Thirdly, going slowly. I've read innumerable books over the years about techniques for getting greater lasting pleasure from sex. The only one I've ever been able to utilise is the injunction to keep breathing. That is, until I discovered the 'slow motion' approach. This simply means that whatever speed I would normally do something - kissing, touching, thrusting - I now endeavour to do it half or a quarter as fast. This requires no skill other than remembering to put it into practice; but in my view, it surpasses all techniques by miles.
So that's it: daily choices; the intention to avoid orgasm; go in slow motion.
For my wife, happily, it turns out that the more she tries to avoid it, the easier it has become for her to orgasm. I say 'happily', not because she particularly wants to orgasm, at least not at the moment, while we experiment with non orgasmic sex, but because for much of our time together her orgasms from intercourse alone have too often been the result of far more effort and strain on both our parts than seemed desirable. Now, we find it's no effort
at all, but simply a matter of waiting for the orgasm to come. It's analogous to a pan of milk on low heat. Eventually, it will arrive at a satisfying, rolling boil. Previously, it was like trying to boil that pan of milk by subjecting it to frequent bursts of intense heat from the wrong place for too short a time.
The second postscript also concerns my wife, or her vagina. Her vagina 'opens' during intercourse and 'closes' after orgasm. In the past, when she's had intercourse and not reached orgasm, she's often experienced the not entirely pleasant sensation of her vagina remaining 'open'. She's noticed this a lot recently, since we've been deliberately avoiding orgasm. We both feel an 'open' vagina has a sense of incompleteness about it.
This hasn't helped either of us to be convinced that there's any more downside to orgasm than the loss of opportunity to experience lovemaking without it. Maybe that's enough, or maybe we haven't gone without it for long enough. Time will tell.