trying for five years

hi everyone. As much as I am trying to convince myself and my husband that we don't need to have a child together after 5 years of trying, I can't help but cry nightly that we may never have a child of our own. As a blended family I have an 11 yr old son from a previous relationship and my husband has two daughters 11 and 17. Will I ever find satisfaction with the kids we already have and acceptance that this may never happen? I say "we don't want to start over" and "our time to travel is coming fast" but it's just natural for any couple to progress toward expanding their family. Because of all my emotions swaying back and forth, I am losing interest in pleasurable sex and focusing only on reproductive sex. I know there should be good balance but sex reminds me of the failed attempts in the past. all type of issues. so sorry for venting...