How do you ladies feel after your partner cums inside you?

I just want to know if my experience with it is common among other women.

I have an IUD and I've had it since February this year. And today when my SO and I were having sex, I wanted him to cum inside me without a condom. We both love each other so much and we're planning on getting married. So he agreed to cum inside me without a condom. I barely felt the cum when he finished, but it felt so good to finish together. Immediately after, it was messy and running down my legs, and it felt like a water balloon was inside me about to pop or fall out. And it's almost 3 hours past when we finished and I feel cramps. Is this normal?

What are your experiences with your partner cumming inside you?