After 7 years, he still has trust issues

I have been in a relationship for seven years. My boyfriend has doubts about me and thinks I am chatting with someone else. I can’t do anything. He never understands me and always says bad things. I am really worried about my life, and we are planning to get married. I don’t know if he will do the same things after marriage.
If someone behaves in this manner after seven years of being in a relationship, it’s safe to assume things won’t change after marriage. Your sense of helplessness won’t go away and may end up becoming more acute. This isn’t what any healthy relationship is like, so you are right to be concerned. Also, if you have doubts and are worried about something specific, making a lifelong commitment requires a lot more careful thinking. Weigh the pros and cons carefully. I suggest you speak to your family and friends about why you feel the way you do, and get a sense of where they stand. Tell them why his behaviour bothers you because they have a right to know. You may feel compelled to marry given how long you have been in this relationship, but it isn’t something to be taken lightly, especially if you are already harbouring some serious reservations about this person.

I have tried to get a girlfriend, but no girl takes me seriously. They treat me like a brother or a friend. I really don’t know how to impress them. Please guide me.
Why assume you have to impress someone when you can simply be yourself and hope that someone appreciates that? The idea of trying to get a girlfriend is also problematic, because it implies that you look at this as a task that needs to be accomplished. If someone isn’t taking you seriously, it’s probably because you are trying too hard. Be natural, focus on being friends, and try cultivating some patience.