It is important to tell our kids that we love them often. It helps build a foundation to our relationships & can help reinforce the trust we build with them. Additionally, our kids learn by our example. Even in times where we are disappointed, frustrated or hurt by our kids actions, it is important that we express our feelings honestly & appropriately & also remind them that we love.
When my husband & I were 1st dating, he would tell me about the conversations he had with his kids including text messages. I asked him if he said "I love you" at the end of the conversation. He admitted that he did not & listened to me when I explained why I thought it was important for him to tell his kids often that he loves them. I think it is especially important that we tell our kids we love them whether we are in an intact family, divorced, blended, single parent, foster family, or adopted family. Our kids learn by our example. As a dad, I think it is even more important that you tell your kids, especially your sons, you love them. You are their role model & it does pay off. When my husband (& myself) exchange text messages with our kids, we always end with "I love you". Sometimes they beat us to the punch so to speak & say "I love you 1st".