Toxic/Destroyer Alphas

How can I know if an Alpha is a destroyer? My Master loves fucking and breeding me, in general he treats me well, he has never done anything that would hurt me or cause harm, but there is something that I can't stop thinking about.

My ass is very tight and his cock is thick, so it is not always easy to take it the way he likes it. Sometimes I say "I can't take it anymore" while he is pounding my ass and he NEVER stops banging, he just slows down, then he says something like "I can stop now baby, but I will be so disappointed, and if I finish I will be so proud of you" Then every time after he says this, I end up saying "please, keep fucking me"

I am sure that if I insist to stop he will, he is a good Man and he would never force me to take his cock if I were in serious pain. However, he never stops when I first say it, he just tries to calm me down and keep banging me in a slower pace until he finishes inside my ass.

I am new to hierarchy and to gay sex in general (I am 20 and only dated girls until last year). My best friend knows everything about my life and she says that if he does not take his cock out of my hole as soon as I tell him to stop, he is toxic, violent, etc. She basically thinks that he is a monster and has been trying to convince me to break up with him. I know she wants me to be safe and happy, but I think an opinion of another fag would be essential before I take such a decision.

He is a good Man and I like when fucks me, but I am afraid this is a red flag for potential worse behaviors. So please Sam, could you please give me your opinion and, if possible, give some examples of Destroyer Alphas? Is my Man a Destroyer? 🙁