I think the trust issue is that the citizen would wonder if the person is marrying them for love, or just marrying them for citizen. I don't see the trust issue as particularly unique-- I'm sure most rich people are concerned if people are marrying them for love or just for the money, for example.
Personally, I would hesitate to seriously date anyone who's future didn't align with what I see for my future. If he's likely to need to move back to his home country, or unlike to be able to have a career, because of his immigration a status then I would have a problem with it. It's not the immigration status itself thats a problem, it's IF that status would limit our life and happiness together. I imagine in some cases things would be worked out easily, and others not so much.