I have a question for you Steven1,
If your partner was to continue as is, very little sex, would you leave or just continue on status quo?
I'm in a similar position as many, many other men. I've looked around at hundreds of posts about this sort of situation generally the pattern is the same:
1. Guy not getting any, ranges from once a week to once a year or less.
2. Guy loves his wife/gf and presumably wife/gf loves him back.
3. Woman often is 'too tired' or something similar <---- this comes up a lot. I'll come back to this.
4. Man tries to do whatever he thinks it takes to address that 'too tired' problem.
5. It doesn't change a thing, not for very long at least.
I see it time and time again, it does not work to 'do more chores' or whatever you think will help her not be 'too tired', not for 90% of the stories (I followed lots along to the end of the thread). It could be higher than 90%. In fact I can't remember a single thread/story that ended 'I did more of the work around the house and now we have sex all the time, it's great, thanks everyone'.
Many of these people and their partners sought councilors. Sometimes it helped, more often than not nothing changed.
Now lets look at this 'too tired' comment.
I ask you to think back at exciting times in your life. Times when you were most certainly tired, but still did rather physical activities. Skirmish is a great example for me, even if I'm really tired the moment I start to get into skirmish gear I start to get rather excited and I have plenty of energy for the next 2 or so hours. Adrenalin and all that. The point is, the emotional excitement is plenty enough to overcome and physical feelings of tiredness. It doesn't even have to be anything adrenaline pumping, think of those times were you are again tired and just thinking away in your head, when all of a sudden you realise the solution to a problem you are having, BAM you start to get aroused and wake up, physical tiredness be damned.
Well, what happens if this 'too tired' is more a problem of "I'm not aroused by you" In other words, 'at the moment I'm not attracted enough to you to have sex'. Then the question becomes one of 'What reasons could it be she is not attracted to me' rather than 'what do I have to do to make her feel less tired'. The answers to each question can be very, very different.