what are the antagonists to marriages and relationships.

well, i must say that there are many things that stand against relationships, the things that always oppose the love you share is not really specific, that means that there is no constant thing that opposes but whatever is an opposition would come in form of a temptation.
Marriages don't always break for a particular reason but all the reasons was as a result of not resisting temptations.

So make yourself temptation resistant

What a cliche. How exactly do we "make ourselves temptation resistant"?

how do i get my boyfriend to stop acting big and bad around my friends

what kind of lies do nigerian women use the most?

Simple respect goes a long way. Ladies if you're talking to your husband on the phone don't have conversations with men at your location while not paying attention to what your husband is talking about during the phone conversation. That's disrespectful.