I'm married to a man, but am openly bi-sexual and have never had a problem with it. I am also very open about this with the kids I work with at high school, particularly when they use gay as an insult. Once I had a kid I was working with talking about gay people saying she 'hates them all and they are so weird and if ever found out a friend was gay she'd not talk to them again.'
I promptly got up and moved to another child in the class. When asked by original kid why I simply stated that 'as I'm bi-sexual and therefore gay I assumed she would not want my help!'. She started making puking noises but did seem a little embarrassed!
I have got in trouble from a few staff members who are uncomfortable with my openness (You are married to a man so why say you like women to the kids) but I am now the 'mother figure for loads of gay students who are struggling. I had one ex-student and her GF, who she was with at school thanks to me giving them 'the push' say if they ever got married I would be invited.
My son has no problem with same sex relationships at all - we have LOADS of gay friends and one if them is even his honorary 'auntie'! :)