Initially, she is a sweet and innocent young girl, roped into to marrying Pablo young due to pressure from her family. While they disapprove of Pablo –– especially her older brother –– their rigid traditional values influence them to tell her that if she's going to run around with a boy, she should be married to him.
As soon as they are married, Paty asks Pablo if he will be faithful to her forever; he of course agrees. This is a blatant foreshadowing. Not long after, Pablo is back with the prostitute and later, many, many different women.
At first, one might think this is the same old trope: jealousy, perceived or real infidelity, misunderstandings, broken relationships. However, I think the writers are intentionally playing with representations of gender and what is accepted societally.
While her efforts are without reward, she continues to try to balance between being a good wife and sticking up for herself. Despite her best efforts so far, Pablo has used (what he thinks is) charm to avoid her attempts to confront him –– about other women, about his business, about always being away.
I think the contrast between Paty and her mother in law are an attempt to cause the viewer to question how women are treated and represented in real society. She represents a struggle many women face –– being strong and assertive yet struggling in a –– typically –– male-dominated society.
The deeper I get into this telenovela, the more I will be able to see how the writers play with Paty's role.
Will they allow her to have a voice, or will Pablo continue to squelch her?
In either case, it will provide an interesting commentary on the role of women and the representation of women in society, ranging from old traditionalism to new modernist ideals.