To understand the changes to the diplomat visa, a bit of background is necessary. Though the UN has been in headlines regarding this change in policy, it applies to all diplomat visas, not just those of UN workers.
In the past, same-sex partners of diplomats living in the US for work purposes were considered as falling under "family". Now, under the new policy, same-sex couples would need to be legally married in order for the diplomat's partner to qualify as family. The problem is that, in many countries in the world, same-sex marriage remains illegal, meaning that some couples will no longer qualify. According to news articles, around 100 families in the US will be affected by this.
One consolation is that it doesn't seem like regular partner visas are at risk. But the gay rights advocates feel that this is a strike against LGBT+ rights in the US and it does seem to be part of a general move towards more conservative views and policies in the current US government.
A couple of good links if you want to read more:
I wouldn't be worried.
According to a recent survey, 67% of Americans supported same-sex marriage. The laws aren't going to change any time soon, and it is likely that you won't face many difficulties caused by the US goverment directly.
Hope this helps!