I realize the children are still pre-school age, but how committed has their father been to the homeschooling? Your ability to educate them yourself will depend heavily on his agreement and support. If he is also heavily invested in them being homeschooled, you can, and should, ask for sufficient child support / spousal support to make that happen. To do that persuasively, you will need a pretty detailed budget of your living expenses and schooling costs. You will want to nail down what curriculum you intend to use, knowing that you can always switch curriculums later, and whether you intend to ask for support sufficient to allow you to stay home and educate them yourself, or to hire a nanny / tutor who can provide both childcare and education while you work.
If their father is not dead set on them being homeschooled, he likely won't agree to any of it, and quite honestly, it's very unlikely a court would order the additional support money. Also, if their father wasn't or is no longer supportive of homeschooling, his wishes can carry tremendous weight with the court in requiring you to enroll them in public school. I have a friend in this situation, and it's been very difficult for her. Even through she is remarried and financially able to stay home and homeschool her daughters, her ex husband insisted that the court make it part of the decree that they be enrolled in public school.
I would love to hear back from you with more of the current and projected situation. As a homeschool mom, this is a very pertinent topic for me. Best wishes to you!