Everything in life has to be replaced. Remote control batteries, teeth, friends, mobile phones, fridge food, clothes, women...nothing can stand the test of time. You don't have to permanently settle for anything. Stay with someone for however long you want, then when you get bored and want a change, find someone else. When someone better comes along, you can upgrade. You don't need a soulmate, just sex basically, and you can get that without too much difficulty.