<human>: My girlfriend and I are not particularly religious though she was previously in her life.  Her ex is pretty religious as is her oldest kid (15).  We've been together a year now and regularly spend the night together at this point.  Our parenting schedules aren't 100% the same so we have some nights where we have no kids, and some nights with just mine or just hers.  We don't live together so generally if no kids are present and one of our houses, we spend the night at the others.

Apparently it makes her 15 year old (and her ex) uncomfortable that we spend the night together when her kids are around.

This doesn't seem to affect the relationship with her other kids (she has 3, I have 2) and my kids since they weren't raised religious don't have any opinion on the matter.  In fact, I have a great relationship with her other 2 and my kids love her.

I'm not sure what to do.  Because of our different backgrounds and beliefs I see it as likely that her oldest and I are never going to see eye-to-eye.  He's also the oldest and is likely to be more upset about either of his parents dating or "moving on".  That doesn't matter to me and I always provide him the same support and love I do for the others.

I'm also of the opinion that it's ok for kids to be uncomfortable and it will either harden their beliefs or teach them to re-evaluate and be flexible with others that don't see the world as the same (you know, co-exist).  That said, I don't have the same religious background they do.  She hasn't made a decision about how to handle this and I'm not sure I can provide reasonable guidance here because I don't understand basing behavior on a 2,000 year old code of conduct let alone allowing a child's belief in that code alter our behavior.  

Has anyone else gone through something similar?  Any guidance?

Can you condense the text into three sentences or less?
<bot>: Very christian 15 year old and his father (the ex husband) have a problem when his mom and I spend the night together and doesn't want us doing it when the kids are around.  What to do?