It is better to have love and lost than never to have loved at all
as romantic love, operationalized as marriage (though I surely don't), then Tennyson has been felled by science - the data show that it's just not true. In happiness, health, longevity, and just about everything else that has been studied (except maybe wealth), people who have always been single do better than people who were previously married (divorced or widowed).
As is often the case in marital status comparisons, the differences can be small. But they are quite consistently in the opposite direction than Tennyson would have led us to believe. (I provide a critical overview of the research in the science chapter of Singled Out. Karen Rook and Laura Zettel reviewed studies of physical health here.)