My sons biological dad is inconsistent, disrespects and degrades me as a person and a mother, should I give in and let him take my son when he wants?

by Destiny
(Selkirk)

Hey mothers, my son's biological father has just finally started trying to take my son for day visits and sleepovers, but the issue is, he only asks when its a special occasion or only once or twice a month or every other month(I'm sure this is inconsistent), he doesn't offer anything or financial help for his own son, whenever he buys my son anything, my son isn't allowed to bring it home.
He disappeared from our lives 2 years ago after he told me "I give up and you're the reason"
I just feel like its unfair to my son, because since then he's been fathering his girlfriends 2 children rather than his own, and now he feels entitled to my son.

He often gets his girlfriend or his mom to message me(he is fully capable of messaging me himself) we have no legal third party agreement, he's also not on my sons birth certificate. When he does message me himself he degrades me and says the most nasty and disgusting words, then expects me to be nice and to give him what he wants whenever he wants(my son).

I do have a boyfriend who I have been with for the past 2½ years, we are very happy, my son calls him dad and is very close with him, I just feel like I'm confusing my son with his inconsistent biological father if I let him take him and call himself my sons dad.