Just like a house, it seems to me that a relationship, of any kind, can go through the toughest times when the foundations are deep and strong enough.
And where a house is usually founded on iron and concrete,
a relationship is founded on trust and honesty.
Without this, nothing you ever want to build has the least chance to stand over time.
And just like it takes a long time to structure the right foundations before building the actual house from the ground,
It takes a while to build a healthy trust-based relationship before building a family.