Sex after vasectomy

So my husband got a vasectomy almost 3 months ago and did a home check test and it said he’s sterile. I don’t trust those so I said he needed to do the test by the dr. Today I’m supposedly ovulating so I told him to pull out & he DIDNT!!! I’m so nervous because I don’t want another baby... esp since it would be 3 under 3. I’m taking the plan B even though I know it won’t work if I am really ovulating. Hope I’m not or I hope he’s sterile. 😫😫😫😫 Needless to say I said he had to be tested ASAP bc I’m not gonna chance it anymore