Models and Morals...

Somebody once said, "Nothing is perfect.". Applying the same to
achieving a happy relationship, does it implies that a person
may have to look out for more than one special "one", so as to
have all that, that he has dreamt for in his spouse.What if you find yourself in a situation in which you are sexually attracted to one person and emotionally to another
(Which by the way, is a fairly common situation).

Does the fact, that a person may be having two seperate
relationships because his "needs" (NOT sexual, particularly),
weren't been fulfilled by one, makes him disloyal towards one or
another...??? Humans by very nature wants the best for
themselves. We use our computers for gaming and our mobiles for
making calls only, not for playing games because apparently we
want a "better" resolution in games.

Even in sexual sense, everyone wants a model in bed...but when
it comes to emotional support, we want someone with moral
values (and models surely aren't that "moral").

When this concept is followed in real life, with humans, a
person often finds himself unable to decide which relation to
keep and which one to let go, without being unfaithful(if thats
possible).So,I guess one could help but wonder:
Multiple relations-In or Out...???