when i was little, i didn't have a dad?

Times flies and I have the sense things will get harder. Use to think that I  wanted to have someone in my life so that my son would grow up knowing someone as their dad, someone to be there helping him out but due to my shyness, and circumstance I just had so many other things in life than to devote my life to seeking a life partner. Not my mission in life but it would truly make life easier or happier.
My son just asked me, "When I was little, I didn't have a dad?"  How do you answer that? He does and he doesn't and he does and I can go back and forth with all the answers. So I asked him, "Do you have a dad, now?" and he said, "Yes, he's outside." Referring to my dad... So, it's tough he's 5 yrs 8 months so very close to 6 yrs and starting kinder on  Wednesday. I know kids comes to so many realizations and I know he's growing but so many challenges do scare me a bit.
They're truly unavoidable. But, the thought of those questions will be tough surely.
I also start thinking what will happen if someone comes into my life. Will they be willing to take the challenge of a single mom with her son. Will they try and love my son as their own? They have no choice but to accept if they want me but I wonder if someone can handle the challenge. Will someone ever love me enough to accept me for everything I've got? What i
It's hard to ask someone to do that, I know. I don't even know if I would accept me, lol. Well, I'm biased.
About a year ago I went out on my first official date where the guy came to my house, and rang the door bell, and well my son saw I went out with a guy and threw a fit. He's a very jealous little boy. I'm hoping he will understand but he's still young. I guess my best bet is for who ever comes in does his best to win him over. It isn't too hard but he has to trust you. I think my son's reaction truly did make him realize he wasn't ready and gave me a lesson in motherhood even though he has no kids, and then assumptions of a lot of single mothers... well, you would think that if you saw some similar behavior you would be more understanding with single mothers, it's very easy to judge and try to make others see you points of view yet you wont want a single mother because of it.
oh life how i love thee for the challenges. i know i would avoid people the trouble by staying single but the heart screams out for love and companionship... will my son and I ever be accepted and be truly loved?... I hope so but I don't expect it to fully happen... I guess sometimes I set it up that way just in case. No one wants to be vulnerable enough but there's a point where you know you've past the point of not wanting to turn back and no matter what you want it to happen.
I guess, I have all the experiences as guide and I use other's also. I've very observant and take everything in. I'm a sponge but I also reject a lot. I'm sorry, I'm not very interested usually. it's very rare a person actually catches my eye.
Anyways, yes so many things to look forward to and fear all at once. I try not to think but I can't help it.