Some relationship doesn't actually cost cost all the time, what i mean by cost cost is, You spending or given up somethings you were doing before you meet that person. But some relationship will make you start doing things you were not doing before. Like someone mentioned of quitting clubbing, or stop smoking and so on, Some relationship will even make you start clubbing and hanging around with new friends. depends on who you meet, if she/he is the type that loves to dance some weekend, You will be forced to club... maybe you are not that clubbing type, and for you to make that person happy, you have to at least club one or more with her/him when the need for that arise.
beautiful... nice one! Never really gave this a try; true, some relationships can cause you to learn and adapt to a negative lifestyle. In that case, it may have cost you your serenity, your SANITY