Me Too! Can't do it to save my life. There are these mounting stirrup thingys you can buy. They fit into the stirrup and hang down and give you an extra 8 inches or so, then when you are up, you remove them and put them in your pocket.
In an English saddle, I can lower the stirrup to its' ulimatel lowest point, get up and then reraise it, but WesterN/ ?? I am up a creek if I ca'nt find a big log.
If a friend , who can mount more easily than I, will hold the off stirrup for me, I might be able to lierally "climb" the side of my horse. Can't feel good to the horse, though.