I just think that once married, people change their behavior towards one another. For example, before marriage, people want to spend time together and do things for each other because their relationship is relatively fresh/new and they want to stay in the relationship to eventually marry. Once married and with time, they fall into a routine and start to feel comfortable and safe in the relationship so they no longer need to do many of the things they did when they were going out because they already have that other person permanently in their life. That's my far-off view of the subject. Then you have all the personal issues with people, expectations, extended family, etc, etc.
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