Hi, Karl —
Thanks for your question.
It is always a sin to have sex outside
of marriage. There are no exceptions.
Addressing your second question:
Sex between a married couple has
two components. The unitive and the
procreative. A married couple is
free to have sex any time they want
so long as they do nothing to artificially
frustrate the procreative bond
If one or both can't have children,
there is no reason why they can't
express their love for one another
through the gift of (sex|natural
conjugal love) which God gave them.
It is a very unfortunate misunderstanding
that married couple's can't have
sex for pleasure.
All the Church
teaches is that the couple has to
be open to
new life. As long as:
- the couple
doesn't engage in artificial contraception (i.e., the pill,
condoms, etc.), and
- the couple is open to new life and
that includes couples who, for
medical reasons, can't conceive.
they are open to new life, God
can always work a miracle.
This is one of the most widely
recorded miracles in the Old Testament.
Many old couples in the Old
themselves having miracle pregnancies,
starting with Abraham and Sarah.
Abraham was one hundred years old
when he had a child, Isaac, with
Sex between married couples is more
than pleasure, it is unitive. You
both give each other,
to one another.
Your concern is for each other, not
for yourselves. The man gives himself
to his wife and is concerned with
pleasing her, not himself and vice
versa. Of course, this total
is open to life, even if it seems impossible.