Sometimes we experience a failed love affair. Will these failed love affairs lead to karmic debt? If so, will we be born again and repay it by making the love affair work? Will a love affair failed now lead to union in our next birth?
Karma is a highly complex issue. There is no yes/no answer.
Karmic knots can be dissolved in our own heart and consciousness, without having to relive those relationships which failed.
On the other hand, yes, strong emotional bonds are a magnet which might end up pulling two souls together again, to work things out.