Why have we seen an increase in the two-body problem? There is less of a gender imbalance in Ph.D. students, particularly in the sciences, than in the past. Most Ph.D.'s spend nearly all of their working and social lives with their fellow students and romantic entanglements naturally develop.
How do you avoid the two-body problem? Find yourself a non-academic partner. You may spend the rest of your working life spending time with academics, do you really want to spend your non-working life with them as well? You have to work to find a non-academic partner. Join some clubs, preferably outside the university, that match your interests. You'll meet people who share at least one interest with you. Use the on-line dating sites, let friends set you up. It will take some work to find a partner but maybe you'll fall in love with some nice MBA. That's what happened to me.
Of course you may just end up in an academic couple. After all, you just can't stop true love.