dontno There's a wonderful poster on here called secretskillrelationships and I hope she comes along soon. I also hope she won't mind me sharing her story with you, it has echoes of your own. Her H had a one night stand many moons ago and never told her for years. Until that point as I recall, they had been very happy indeed. Afterwards however, the H never seemed to fully commit to his marriage. The effect was pretty subtle, and the poster could not put her finger on what was happening. He kept saying everything was fine.
The truth did come out though and he finally admitted that since that ONS, he had convinced himself his marriage was never going to be what it had once been. So emotionally, he checked out of the relationship. You can imagine the turmoil for our poster. They are now divorcing after 20+ years of marriage.
This is a shocking waste, all for a bit of honesty. People really underestimate how pernicious secrets are, not just to their partner and their marriage, but also to themselves. I have often posted on here too about a good friend of mine, who had been feeling guilty for years after an undisclosed affair. Her guilt was so enormous, that she put up with awful behaviour from her H. The long held secret came out at Relate counselling and although there was shock and hurt, their marriage is now one of the happiest I know.
Can you sit your H down and say (assuming you do feel this way) that you fear that he has such a secret and can forgive now, if there is honesty. Generally, as soon as a couple starts to communicate with genuine emotional honesty, it has the most incredible effect on their intimacy.
Now of course there are several other ways this could go. He could still deny, in which case I'd suggest you tell him what you have told us; that you want to be more emotionally close - and to have a more frequent physical relationship. He might admit something, including feeling disengaged from your relationship and he might finally admit defeat, or he might admit and you feel huge resentment for all these years of a "veneer" marriage. It's a risk of course, but there are high gains to be had too. There is usually some work to be done after disclosure and in a case like this, counselling can really help.
I think this will always be in the back of your mind - did he once have an emotional attachment to someone else? Is that why our marriage is so superficial?
I always believe the instinct you followed to post this after such a long time should be heeded. At some level, perhaps you feel it is the right time for this to be finally unveiled.