Aslamu Alaikum! Brother I'm suffering from social anxiety (or with some other phychological disease). As I can't afford therapy because I'm not financially well. So i don't wAnt to get married because I don't want to intentionally ruin someone's life. So, is this a valid reason for not getting married ? What Islam guides us about this?
InshaAllah things will get better for you. Marriage is not obligatory, therefore you always have the choice of not marrying. Regarding your situation, you can wait and things may change a great deal for you in a year or two. There is no problem with delaying marriage for now, but there is no need to say that you will never get married, since you never know what the future may bring. You may one day meet someone who doesn’t mind your social anxiety and who can take care of you financially.
Do what you can with what you have, and always try to increase your knowledge through lectures and books, and inshaAllah you will be able to change yourself and your life for the better.