I like the concept of OTL but I don't really enjoy the stories when they present the two lovers as soulmates. I 100% believe that two people can truly love each other and be in love for their whole life. But, as you said, there is work, trial and error, and they choose to be together.
I don't like OTL because what about people marrying multiple times, for example. Just because a person's first marriage didn't work about whether by death or divorce, it doesn't mean that they didn't truly love each other at one point or that they won't truly love their future partners