They didn’t get married till ‘89, he was already Governor. So they were merely “dating” whilst serving together.
Do you think then married Howard Baker (Ev Dirsken’s daughter, didn’t know that, died 1993) “dated” Nancy Kassebaum whist they served together?
I would imagine the first congressional hookup was between a couple of dandy gentleman way back when. Perhaps James Buchanan and William Rufus DeVane King.
As you hinted at, Buchanan and King not only were rumored to be Friends of Dorothy, but to be a couple. I’m not sure how much of that merely can be attributed to the virulent politics of the 19th Century.
Senator Pete Domeneci was married throughout his Senate years and never dated any fellow members, but he did manage to knock up Senator Paul Laxalt’s daughter.