There are some persons in each one's life that are indeed irreplaceable. You'll never find a substitute for your mother or for young younger sister. But for a boyfriend or a girlfriend, you will! The world is big and it doesn't end with your actual partner. But if you really love him and you ask yourself how to make the relationship last, here are some answers that could help you.
First of all, if you know from the very beginning that you want a serious relationship, you should be very selective concerning your partner. You can have many dates and you can choose only one, that one who is more compatible with you and your personality. As a tip, you can go on the internet and look for a site for dating. There, you can describe yourself and say what you are looking for. Or, if you don't like the virtual way, you can go for something "live", such ash going to all the parties where you are invited or going out more, in general. You will certainly meet new people and you can choose the one with you want to have a serious relationship.

Expectations in a relationship are very important. If we expect to be happy and to see the entire world pink when we are with our partner and this doesn't happen, then we'll get disappointed, and, of course, we won't need that relationship anymore. Before having something serious, people should know each other expectations. But don't forget: you aren't allowed to demand too much and to offer too little! Or, another case is when you know that your partner has some imperfections, but you try to change him. If you won't succeed, again, you'll be disappointed and you'll want to finish with him.
If you love someone and you still ask yourself how to make the relationship last, you should know that it will be a very difficult job. But if you know how, you will be very happy with your soul mate.