How do I tell my mom my long distance boyfriend is coming to meet them?

I honestly don't think she needs any warning. Telling her in advance can put extra pressure on him to ask her right away, when perhaps he wants to get to know your family a bit first. I agree with everyone else saying not to get too involved with him if you have never met in person. People can be very different online than in person, even in a video call. You owe it to yourself to make sure this is a safe situation before making any big commitments like marriage. If you have met in person, then good for you. I'm glad that you two can finally be closer together.

I agree with Teardrops, if you haven’t met them in person or spent long periods of time with them you really can’t determine what it’s like to live with them. If there is a way to ease into living with each other I’d say do that. You may end up with someone you thought was all those things only to find out you’re stuck in a lease agreement or something like that with them. By no means am I trying to put a negative connotation to your relationship with them. I’m just speaking from experience. Now on the subject of your mother. It sounds like you are afraid of what she’ll say regarding this person moving in with you. If you’re living with your mom I can understand your concern. If not and she doesn’t tend to be supportive of your life decisions then you may try doing what most people do when they are in a new relationship. They wait until they know that they really are someone that they want to spend their life with before introducing them to their parents. It’s very common. If your mom is completely unwilling to support you in most things it may be that you just have to do what is best for you regardless of what she thinks. Just be careful and approach it in a tactical way. Study good ways to present the idea to your family. There are psychological tactics that can sway her support to you favor that can be found online. First try googling “what is the best way to tell my parents of my new boyfriend/girlfriend?” There should be something helpful out there.