Spend time together, stronger your bonding will get. No matter how busy and occupied you are, always arrange the time for your partner. Along with sharing your personal feelings, you can let each other know that how was your day, what was special, etc. and never forget to realize your partner that you missed him/her.
Marriage is not outdated at all... it may have evolved over the years..But I don't think people have given up on marriage. In fact, they have fought for the institution. Think same-sex marriages that have been legalized in the US not very long ago... There may be increased cases of divorce and stories of relationships collapsing but that does not mean it happens with everyone... there are lots of positive and successful marriages as well...