Ben was comfortable with me exploring it, and I casually went on a few dates.From there, we talked about opening the relationship on his end as well, and I was surprised by how nonjealous I felt.I dated someone for over a year, and the consistency (and depth) was really nice.
We've honestly become closer through sharing our dating experiences with one another.
At first, we were monogamous (I was 18 and didn't know much about any other relationship structures).
Ben mentioned that he would be comfortable with me casually dating other people early on in our relationship, and it was then something we talked about every once in a while for a few years. When we graduated college (and moved in together), I met someone who I could see myself dating.
We took it really slow (lots and lots of conversation) and occasionally dated outside of our relationship.
As time went on, the "casual" piece has become less and less important.