What defines 'work'? I don't feel that our relationship is unpleasant work.
But throughout the last 15 years we have had times where we have been distant from each other, sometimes actually physically with DH's travelling. Sometimes a bit like ships in the night because of kids and jobs and all of it. But we both notice when this is happening and then make an effort to re-prioritise each other.
Just simple things like moving from opposite ends of the lounge to snuggle up to watch a film. Giving him a buzz when I am going shopping to see if there is anything he needs. Sometimes cooking stuff I can't stand because I know he loves it. Being brought a cup of tea in bed on a weekend, him stroking the back of my head as he goes past (and lots more). It is the little things I think that really add up.
DH and I also just tell each other straight up what we need at any particular time, there is no hedging or head games or expecting the other to guess.
We have arguments, not many and never violent (though there have been some where I have had to control myself from throwing whatever I have in my hand at him [not a great idea if it happens to be a cast iron pan for instance]), we haven't done the proper slam door and leave type argument since our first year of marriage together.
When someone loves you, you have a lot of power to hurt them, I try to be very mindful of that when we are having an argument. So that is work.
The family we have made together is so good, so amazingly good that I sometimes wait for the crash, it seems that I cannot have been this lucky, that something awful must be about to happen.
So I think we do 'Work' at our relationship but almost the work is the relationship if that makes any sense.