NLAS,
You're under so much pressure. Because it's not just your mother and abuser step-dad, there's also a particular cultural expectation that your life does not belong to you, and that planning for and matchmaking YOU is something other people can do without your permission, and they're all free to speculate about you as though you were a prize heifer.
Even if she weren't an N, your mother has the excuse of her culture--to interfere, smash boundaries, and treat you like a possession or an object for sale on EBay rather than a person.
It will take a lot of clarity and strength to decide how much of your original culture (and their support) you're going to enjoy and work into your life, and what parts you're going to leave behind. Culture is fluid, like phamily. It is changing and being modified in every generation, all the time. And free human beings, who are not slaves, have a choice about what they want to perpetuate.
There's a cost to permitting so many disrespectful intrusions, literal and metaphorical, and you have already paid a lot of it. I do think you're building the clarity and strength you will need to draw boundaries for yourself, and stop being her canvas.
As to stranger swains who may be making assumptions about you based on her false information? You know, you are not responsible for protecting them. They'll manage their disappointment or confusion just fine. They will not be harmed if you simply say the truth as you have been: "No, I am not available. My mother is confused and did this without my permission." But it might be nice to just change your phone number.
(BTW, "not available" -- you don't even have to tell those males that you're involved with another male, in order to have "permission" to say No to them. You are allowed to belong to yourself. This is what Not a Slave means.)
I had a friend in grad school who first taught me about that. She wouldn't answer the phone or the door not for any dramatic reason, but just because at that time she was thinking, or painting, and she just valued her own mind's freedom. A ringing bell obligated her to absolutely nothing.
love,
Hops