A sign that you may be in a healthy relationship is that you're learning.
You are learning about yourself, the relationship, and your partner.
What are some lessons you may be learning?
Communication.
You are learning how to talk about difficult topics with you partner... the best way to bring them up, when is a good time and when is a bad time, whether you need multiple conversations to solve an issue or just one.
Maybe your partner needs a heads-up that the conversation you're initiating is a serious one, so you've learned to ask, "Are you in a place to talk about something with me?" instead of just jumping right in. Or, maybe you've learned that you need physical touch during a tough conversation, so your partner has learned to hold your hand.
Compromise.
You are learning about giving, and you are learning about accepting. You are learning about the areas where you have flexibility as well as the ones where you don't, and you are learning about where your partner has flexibility and where they don't.
For example, you know that, as much as you like to sleep in a few extra minutes, making a new habit of waking up as soon as your alarm goes off is worth it to help your partner, who gets really anxious about being late.
Moods.
You are learning to notice when you are becoming frustrated or feeling unimportant. You are learning to let yourself be seen and noticed, and you are learning to let yourself be known.
You are learning when your partner is hurt and when your partner has just had a bad day. You are learning when your partner needs a hug or kiss and when your partner needs a few words of affirmation. You are learning what it looks like when your partner is happy.
In a healthy relationship, you're an A+ student, and the subject is your partner.
(And, for the record, it goes both ways -- your partner is an A+ student in the subject of you.)