The last time with stepMOMMY

I am your stepMOTHER. Several weeks ago, we gave in to overwhelming desire—a sexual encounter that left us both thrilled but incredibly guilty. We agreed it was a mistake and wouldn't happen again, but resistance broke down.
We agreed one last time, but this time you wanted to finish inside me. I was reluctant, realizing we weren't using protection. I eventually gave in, saying it should be safe enough since it was the last time.
One week later, after your stepFATHER left for work, you touched me. I tried to resist, citing our last encounter, but you reminded me it was your first time. I felt guilty about taking your virginity, yet excited. I gave in again, but you insisted on cumming inside me. I tried to use my authority to stop you, but you sped up and released inside me.
Two weeks later, your stepFATHER left for a business trip. I thought our kitchen encounter was the last time, but you came in. I was filled with guilt and excitement. I gave in, saying it had to be the last time. For real.
The rest of the trip became a sex marathon. We didn't use condoms, each time thinking it was the last time. The risk only made it more exciting.
Today, we're on a stepfamily beach trip. You get an erection seeing me in my bikini, and I motion for you to join me in your room. We've become bolder, stealing time together even when your stepFATHER is home.
We still sneak around, but the extra risk has only made our affair more exciting. "This is the last time" is now just a habit—a cover for our ongoing taboo relationship.
Some weeks later, I'm angry and scolding you because I've ended up pregnant by my stepSON! While I try to stay angry, I can't resist my attraction to you. I guess you can keep cumming inside me until the due date, but after that, never again. This absolutely must be the last time.