When you think of sharing your life with someone, you imagine a situation that involves give and take. You never think of every little thing that could possibly go wrong down the line. However, if you go into situations intelligently, cautiously, and with logic, you'll have somewhat of an idea of how things will play out, and what to expect. At least, to some degree. Having said that, you have to assume that nothing will ever change in a situation for the better, and accept people and relationships as they are.
You can't go into new relationships or date people with hopes that they'll eventually change into someone that will suit you better. Sure, changing for the better, becoming more self-aware, and working on yourself and your relationship is imperative in having happiness in your life. The only thing is, you can't assume that other people will change in the same manner, and you can only control your own actions. In other words, don't expect that the person you're with is going to change, so accept them how they are now and assume that this is how they're going to be for the rest of their life.
Some people feel differently, and they'd suggest that you should not only imagine that this is how a person is going to be for the rest of their lives, but possibly even worse. I'd like to be a little more optimistic than that. I'm not being delusional here when I believe in staying optimistic. Being optimistic is realistic, and thinking in a pessimistic manner won't be helpful by any means if your intention is happiness. The bottom line is, you can stay optimistic, but know that someone may never improve from the imperfections or issues that they may have now. You can hope for people to improve in life, encourage them, and give them positive reinforcement. But, you can't expect them to change, so be wise and think to yourself, can you imagine being with and living with a person who is like this and acts in these ways.
Going into situations with logic and cautious is an intelligent thing that I'd highly recommend. But still, please understand that my view is love over logic. There is no logic to love. Love, and I mean real and genuine love doesn't have rules or logic. It can be a very challenging thing at times, but it's important to try to be with someone in which the situation is based on love, but logical as well. Having said that, if you marry someone or have a life partner that was based on love alone, involving many unresolved or unresolvable issues, your life will not only be challenging, but it could be turbulent for the long term. This type of love without logic can work, and it's possible to have happiness together just the same as if logic was part of the foundation, but it takes a lot of work, understanding, effort, patience, and acceptance. If you or someone close to you falls into this category, don't fret or worry them or yourself. The truth is that relationships and marriage take all of the above to work. Good, happy, and healthy relationships take a lot of hard work by both people.
If you see issues in a relationship early on, it's important to try and resolve them if at all possible in the beginning, and not sweep things under the carpet. Remember, no one is going to be perfect, so simply get that idea out of your head. There will always be issues and disagreements between couples, and even after many years of being married to one another. In a healthy relationship, things will naturally change over time, and that includes everything in a couple's life, including the couple as individuals. This is why it's imperative to make sure you're the best possible match for each other early on, and while the relationship is young and new. Being with someone based on love alone can cause complications, when two people aren't truly the best match for one another, despite the love that they may feel.
Before getting too attached to anyone, or too involved with anyone for that matter, it's important to try and imagine yourself with the person you're seeing, but more so, for a long term basis. If you can't envision seeing yourself with someone forever, and you know this early on, despite the excitement of certain moments that you might share with them or feel towards them, it's important to end the situation as soon as possible. You're never supposed to get close with people temporarily, and only because you're lonely or until someone else better comes along. That should literally be a crime. You might be surprised at how many people are doing that. It's unfortunate, but many people these days are spending time with people, letting them develop feelings for them that are strong, and ending things when the other person starts to act serious, wanting to take things to the next level. This is an incredibly selfish act, and it causes a tremendous amount of pain to the other person.