Based on what you said, not knowing you, not knowing her, not knowing the circumstances, I do not think anyone can really answer this question. If everything else were right, you should not experience this problem. Is this a common problem or something isolate that rarely happens with you? In some cases this happened to me, the girls were virgins and just needed a little more time to build comfort. I cannot stress enough that this shouldn't be happening right and left, but if it's just an occasional prblem, then you might not need (or want) to make lots of changes trying to balance the equation.
I have never used many of Mystery's LMR rules, but apparently they have helped a lot of guys. I did some experimentation, but to be honest this hasn't been a problem enough times to really know much about it. In 50+ lays to date, this only happened a few times. Maybe you should try that, but if this happens very often there is some other problem.