There are many African men in the Nana BTS station area offering services alongside the Thai women prostitutes. Some appeared gay, some did not.
I was just there 3 weeks ago. Finding a woman who was enthusiastic about my size was refreshing, and she wasn't Thai (or even Asian). So, when I'm in Thailand I'm not looking for just Asian girls. I saw many couples in the area, but I figured they were not there looking for male company. I'd say you could chat up any single guy you see in that area, but you might find some very sketchy and/or unfit ones. I aim to return to Thailand in March. Feel free to send me a message if you're still there or just want more info. I don't drink/go to bars, but if you find one in Thailand that couples like yourselves go to, please inform me.