Hi
I'm in a similar situation to Greenman. Sometimes, my wife will take herself to the loo but in recent weeks, she tends to just stand there, look at the toilet and then come back out. Fortunately, this mainly leads to pull-up pants getting extremely "full" with urine.
What I have found that helps, is looking for the signs that she needs the loo (she often gets fidgety, or as I said, goes up to the toilet and hangs around). I then prompt her to actually sit on the loo and hang around outside until I hear that she's "been".
I have found that actually taking her trousers and pull-ups off each time helps, as otherwise, she will tend to get up and pull everything back up before I've had a chance to check (she forgot about wiping a long time ago).
If I leave her to her own devices, she ends up with a full pull-up which eventually leaks onto her trousers. By preempting, we sometimes only get through 1 or 2 pull-ups a day.
It can be very time consuming though and it's not so easy if you get out and about. I have found that on occasions when I have tried taking her into a disabled toilet, she won't "go" with me still in the room.
I find the toileting a very difficult aspect to deal with!