Main meaning of dhamma is “principles” of mind, principles of life… nature of how reality is working. It is very connected to dependent origination. I also like to understand dhamma as “path to liberation”. So when you live in accordance to dhamma, you’re nearing the final goal, final refuge, liberating extinguishment, Nibbana.
And when you’re not living in accordance to the dhamma, the dhamma (life) teaches you through suffering that you’re not doing “right” things and when you’re doing them, the suffering will come, thats how it is, thats the first noble truth and workings of kamma.
But doing this “mistakes” (not really mistakes) is a learning process, rising in dhamma through experience that we are all going through in our own tempo and way. As long as you perceive this situations with mindfulness and wisdom, and you don’t look just outside, but especially inside, to reactions and feelings and dillemas of your mind, you get in touch with the truth of samsara.
So even if things in life don’t end up well, you’re learning to never do same mistakes again through sufferings (and moments of bliss) you encounter along the path. Eventually you learn that everything in samsara is unsatisfactory and impermanent, beyond your control and connected to suffering going on elsewhere (sabbe sankhara anicca, sabbe sankhara dukkha, sabbe dhamma anatta), and you really start to let go gradually of everything. And when you feel relief of letting go of everthing, of this “heap of suffering”, you start to experience niramisa sukha (bliss born of not grasping) and you really understand what Buddha was meaning, what four noble truths are all about.
In this way, even mundane things when seen with sincerity, constantly & consequently, lead to very importaint insights. So whatever you’re doing: working, loving, breaking up, meditating etc., shows you what actions leads to what consequences… so the life/dhamma is teaching you what actions bring what fruits.
Thats why doing all these things is learning experience.
Thats why Ajahn Chah said that nothing isn’t dhamma. Because everything is dhamma, everything you do is a lesson if you’re looking into relationship of your mind and experience of this moment. In this way you see principles governing this relationship (dhamma), and if you see what ways of dealing with life brings real happiness, and what eventually bring suffering, and you experience it again and again directly, without doubt you will know the truth for yourself… and then you will change deeply.
And well, everything except for Nibbana will eventually lead to suffering. The truth is all the time there if you look at this moment with wisdom. Even jhanas fade away eventually and you’re back into the stresses of life. Thats another huge insight.
And thats the moment when you really give up and enter fully onto the path. I think that is actually part of stream entry.
So whatever you do, just be mindful of relationship between your mind and whatever experience is right now, be it relationship, marriage, celibacy, dounts, thinking, planning, expecting, dreaming etc., you’re on the path of insight. You’re looking at the nature of mind processes.
Even in loving relationship, you will notice how you feel love one moment, and next you feel anger and frustration, the love again… (you can even notice what constitutes “feeling of love”) then again sadness or another thing. You will see that even if your ideals are very romantic, that love is a permanent feeling, actualy reality is constantly changing emotions, no matter how much you try to stabilize them, they’re anicca, anicca, anicca… and this is learning dhamma, learning the truth.
You could also realise how much your partner is anicca and anatta - changing and beyond your control