I'm asking this because i would love to try it with my regular escort, but i don't know if she's up for it. I'm afraid i’ll ruin our relationship if i ask her directly.

If i were you, i would do it this way. When you notice that she becomes boring or that things are stagnating, then you will have nothing to lose and it'll be a win - win situation. If she says no - ok you'll find another one as it already became dull, if she says yes - it will spice up the intercourse and it will be whole another story.