No, it doesn't have to do with sexual orientation. It means he's in the merchant class--works a trade--and from the context, the speaker is looking down on him because of it, presumably because they're of a higher social status.
Compare this line from Pride and Prejudice, set in roughly the same time period:
"Mr. Gardiner was a sensible, gentlemanlike man... The Netherfield ladies* would have had difficulty in believing that a man who lived by trade, and within view of his own warehouses, could have been so well bred and agreeable."
*the "Netherfield ladies" are social climbers who aspire to be part of the landed or titled class.
To quote from the same website: "One thing that may not be obvious is that it is always more "genteel" to be a rural land-owner than to be actively involved in commerce, no matter how much money you're making in business (thus "trade", or business, can be a disparaging word). This is why Mr. Gardiner is looked down upon."