How do you know if it's grown up love?

I've been in such unhealthy relationships that I have this beautiful thing. We spent a whole after/evening chasing a rainbow and taking pictures and videos of it. He does the unexpected. I'm not sure how to feel but sometime I feel scared. I'm 42 and have had 2 pretty unhealthy relationships in my adult life. I know it's easy to say go with the flow but I'd like some real feedback. I don't want to suffocate or loose myself in this relationship. I've done that in the past hmmmmfeeling overwhelmed.

Thanks in advanced.