When a person is in a relationship and they problems with expressing the emotions and avoids emotional intimacy how does that affect the relationship?

Your question is really confusing. Tell us something more. Do you think you have a relationship with someone from your side only? Or you and someone are in in love and both of you have problems expressing your LOVE to each other?

If you want someone and if you think you fall in love with this guy, then go straight to this guy and say that you love him. Or if you think that this guy is after you and you also like him, then your problem is solved. Invite him somewhere you can talk about your love.

Almost all the problems in this Universe have inbuilt solutions. The only thing you require is to know where they are.

Wish you all the best in your love life and all the success in your relationship.