You're supposed to rest your body for 18 months after the first child before you get pregnant again!

It's up to you if you want to be a single mom of one or two kids. Since it sounds like the father will just be a child support check.

Bring them both into the house hold and have 3 incomes!!!

It really sucks that your husband cheated on you. That's awful. But if you didn't want a kid you should be on birth control and using condoms. If you are them your life sucks. If not you do deserve the pregnancy, not the cheating.

Then*

I’m assuming that they are not married. She refers to him as partner. That makes it even worse.

What a difficult and heartbreaking situation, OP. None of us can advise you on whether or not continuing the pregnancy is the right choice, but either way, I hope you and your 10-month-old son have a good support network outside of your husband. You didn’t deserve any of this.

The only good news here is it sounds like your partner is a toxic person anyway and you're far better off getting him out of your life.

People starting their comments with "you're supposed" should keep their thoughts for themselves, they bring no solution to the situation.
It is not a general rule that you must wait 18 months before a new pregnancy. Your body can be ready sooner.

Anyway OP: I hope your partner will understand his priorities. As for such few months between two children can be very tiring the first years (it is also a good way to get done with it at once) but it can also created a wonderful bond between the siblings.
All the best.

Solution? It's an online post, where nothing should be taken serious

Your partner sounds like a dink.