If this is an issue that arises in a brand new relationship - it would probably be a dealbreaker. But if this was an ongoing serious relationship, than for myself, I would learn to adjust. I love sex...love love love it! But love for another person is so much deeper than that. I would hope that we would be able to use other sexual activities and the all-sexy imagination to stay physically intimate.
Stole my answer
I adore the feeling of vaginal sex but not being able to have it wouldn't be a deal breaker. My wife has lost both breasts to cancer and although I always saw myself as a 'breast man' I still love her and want her to be my sexual partner. If I lost my penis in an accident or to disease, I'm sure my wife wouldn't stop loving me either. Love transcends flesh.
Perfect
The other side of the fence.... what about the erectile disfunctional man (meaning he cant get a lasting hard on)? Old age will bring this to most of us.
Yes, the door can swing both ways.
The Golden Rule should guide your actions.
It'd definitely be a deal breaker. Vaginal sex is one of the most intimate moments I can have with my partners. Without it, I don't feel as strong of a bond between us.
At some point in your life you will realize that you can have that same "intimacy" with any one of hundreds of people and when you withdraw the intimacy is over.
A bond is truly strong when nothing short of death can break it.
When you love someone and you are there for them when they need it in a way no one else is, that is beyond intimacy.
I myself at this point in my life would not enter into a relationship which was lacking sexually.
But if the situation changed and I was committed to the relationship - well isn't that what commitment means?
I've done it once.
I can do it again.
A terminal illness can terminate your sex life and consequently that of your partner.
I spent nearly 5 years without sex while my partner was dying.
Besides not being able to have sex there were 3 days a week at the hospital, hair gone, strength lost, numerous surgeries, unable to drive, then unable to walk, confined to a bed.
I know there are people who abandon someone in such a situation but to me that is just wrong. So wrong that it is unthinkable.
I had no vaginal sex for 5 years and yes it sucked.
But my wife had no sex either. And a slow death that came to one much too young to die.