Why can't his penis penetrate me fully?

Hello - I am not the person who originally wrote this post. I am getting married in September.

I have finished my phyiscsl therapy for chronic pelvic pain. I recently bought a set of dilators.

I am not able to get the largest one to go in at all. I have only had the dilators for two days.

I am a virgin. I am not nervous about intercourse. However, I am nervous of my then husband not being able to insert his penis inside me.

I'm 15 years old, and I can't fully erect, and I'm gonna attempt to have sex with a girl this weekend. What do I do?

My boyfriend and I tried having sex 3 times, but he could not put his penis inside. Why?! He is not able to break my virginity.