There are plenty of examples of "mixed" relationships in Eastenders including Muslims with others, even a mixed gay relationship with a Muslim and a non-Muslim.
However, this particular storyline is a reflection of what still happens in real life as well. It will be interesting to see how it pans out. What was objectionable about your first statement was the idea that Muslims are about to take over the countryand destroy our way of life which is patently absurd and a typical racist BNP/EDL line; the other was the idea that it is all right for us British Christians to go to India and force our way of life on them.
Oh, but well done for single-handedly being responsible for Eastenders introducing the Carters.