What makes a realtionship?

What makes a relationship to you, I know ever couple has there ups and downs, when you're good you're good but when it's bad it can be bad...I've been in a realtionship now for about 2 years, some days I feel like throwing in my towel and jist being by myself and other days i love him to the moon and back, sure everyone have there problems, sometimes trust issues run deeper than we seem to realize or just being able to fully be honest, my realtionship isn't perfect and sometimes I dunno if I can fully trust him, my heart says one thing hut my mind says another, do you ever let go of that fear being able to trust someone when there not with you? I'm just always a cluster of thoughts when it comes to being in a relationship I've been hurt bad before I'm sure as to everyone probably felt a simular pain, but what do you think makes a realtionship work? Feel free to share you're thougjts, weather it's been bad, good or the unspeakable.. I just need to hear my ladies thiughts, so I won't feel like I'm crazy lol