Trouble staying in the pen

We have an electric fence because of our last horse to broke all of the plastic fence rails. Now she taught my horse Maia will go right through the electric fence too! I fix everyday, replacing the tape and extra wire but she just breaks it all over again. Sometimes she will stay in for months then she will get out everyday whenever she feels like it. We sold the horse that taught her and have a gelding you never touches it. How do I get her to stay in?

I would just make sure that it is running HOT HOT HOT! Clear all the leaves and grass away, and I don't know how many wires you normally put up, but make sure you have enough rows that she can't army-crawl underneath. Also, though it sounds kinda mean, what we do when any of our animals get out of the fence, we put them in a small pen of the stuff, and keep it really hot, and then when they touch it, they will get a big Powwy shock, because it's so small. Most smart (or dumb, depending on how you look at it!) will only do that once, before they learn to respect it. Just keep a close eye on them to make sure they don't spook through the fence.

We keep our horses behind 1 small strand of wire, and they all stay in fine, even when they are the only ones in there.

Sorry if that wasn't clear; I'm really tired. What I meant was, we put up a small (about the size of a roundpen) pen of wire inside a big corral, and make sure that the wire is tight and running hot. Then, if they get bored (they should be alone) and decide to try to get out, they will get a big shock. But you shouldn't do this if you think your horse might run through the fence or fly backwards through the other side; that could be very bad (that that is why they are inside a larger corral.)
Best of Luck with the rascals!

Thanks. How would you get the wire hot? We have four strands of tape and wire then we put a t-post about every 4 feet.

Make sure there is nothing but plastic touching the wire, no trees, leaves ect. Your t-post should not be touching the wire, other wise the wire will not give a shock. Touch it yourself to make sure. ( your electric fencer is grounded right?)
Do they have roughage in this pen? If they have food/roughage, they shouldn't want to leave. Sometimes investing in a slow feeder pays off, to make the hay last longer.

It does touch a tree and plastic clips but I heard that it doesn't interfere with the electricity. We have a fence tester that says it works and sometimes when I go through there it shocks me. I know it is shocking her because one day when I went go push her off the fence the fenced zapped me through her.

By 'touch a tree' - is the wire running directly on a tree or is it on an insulator that is attached to the tree? If it is the former, you are losing charge because it will travel down through that tree and into the ground rather than continuing to travel through the wire beyond that point. The latter is fine.
Keep in mind, as well, that your tolerance and idea of a "good shock" and her's are two different things.

It directly touches the tree. I will have to fix that and try it...