One word: Tandem.
Mrs. Grouch and I have been riding tandems together since 1976. Most of the tandem teams that we know, the huge majority, are couples who want to cycle together yet aren't well matched physically. As you have discovered no matter how good your intentions, at some point you will find yourself alone at the top of some hill with your wife nowhere in sight. A tandem solves that problem. With a tandem you always arrive at the pie stop together.