That marriage is always better than being single. A happy marriage may be the best thing this side of heaven. However, an unhappy marriage can be hell on earth. Remaining single is not only God's will for some, it is also better than marrying outside of God's will. That differences help in compatibility.
Opposites attract in magnetism but repel in human relationships.
That a successful marriage is void of disagreements. Where there are two people, there will be different opinions. There will be disagreements in any relationship, i.e. marriage. That marriage just involves the other partner. This again is romanticism.