Making questionable choices! Megan Fox is worried about estranged hubby Brian Austin Green after one of his rumored recent flings, reality star Courtney Stodden, shared a video of them in a hot tub, looking worse for wear. Megan, 34, split from Brian, 47, in May following 10 years of marriage, and although she’s since moved on with rapper Machine Gun Kelly, “she still cares about her ex,” a source tells Life & Style. “Megan’s heard rumors that Brian’s on dating apps, hooking up with young party girls, and she just hopes he’s being smart about it. Especially, if their children [sons Noah, 7, Bodhi, 6, and Journey, 3] are around.”…