I don't see anything wrong with it. What's important to some people above all is companionship and family. So if two people settle down together regardless of attraction, they can still have a good life.
As long as it's a conscious decision they've both made, otherwise it's problematic.
I do know gay men that are married to women, one of them is quite open about it. He's not happy, but that's because of the society he lives in that forced him into the union. But he got a son out of it, so I think he said his life has more meaning now.
There are several cases of this in homophobic countries, also for PR celebrity stunts. For example in Serbia & Montenegro the now openly lesbian Marija Šerifović used to "date" the flamboyant hunty Slavko Kalezić back in 2007.
No but I remember like 6 years ago or so I was on youtube and there was this video of a transgender man making out with a straight woman and I was so....confused.
