Re: Should my fiance come out as bisexual to my family? Or? What?
I'm not sure what all the talk about generations is about or why it is relevant.
The only thing that strikes me (and made me guess your age before you stated it yourself) is that you both still care too much about what your parents think. I remember being around your age, doing some things that my parents didn't approve of, including getting pregnant at the "wrong" age (per my parents opinion) and being crushed by the idea that they were disappointed in me or didn't support me 100%. It was a really big deal to me then.
I look back now- about 10 years later - and don't feel that way anymore and realize my need to have my parents approval was because of my age. My only regret about that time of my life is how I handled it. I should have had a very frank conversation with my parents and told them the following:
Parents, I understand that as your daughter you want what is best for me and that you worry about my wellbeing. I am now an adult and I am making my own decisions. You do not have to agree with my decisions, but I hope that we can be peaceful with each other and maintain a relationship with each other despite your opinions about what I am or am not doing. I would like my child to have a relationship with their grandparents. However, if you continue to berate my life and/or my husband and my choices, I feel I have no choice but to separate myself and my family from you. My husband and my child should not be subjected to your negativity and as a wife and mother my responsibility is now to them. What happens behind closed doors is not anyone else's business, including yours. I love you and hope that you will feel comfortable being a part of our lives moving forward."
In other words, I hope that you will realize that what your parents think doesn't matter anymore. You don't owe them an explanation about anything.