I'm feeling totally irrelevant in my current relationship, I feel like I am not loved anymore what do I do?

I am not sure what to do anymore I have been in this relationship for over 10 years and I just don't feel loved anymore. What am I supposed to do? Please no jokes about this as I am only opening up to your answers simply because I am in serious trouble of letting go of this "infernal" situation that I have found myself in. Please help. Thank you