Kourtney was first reported to be dating Travis in January and since then, a source tells ET that the two are "definitely getting more serious and are spending a lot more time together, both alone and with their kids and families." Kourtney shares three children, 11-year-old Mason, 8-year-old Penelope and 6-year-old Reign, with Scott, while Travis is dad to 17-year-old Landon and 15-year-old Alabama with his ex-wife, Shanna Moakler.
Though Kourtney has become "a lot closer" with her 45-year-old rocker beau, whom she was friends with first, Scott doesn't appear to be too concerned. "Scott knows he always has a special place in Kourtney's heart and that he can't ever be replaced and will always be in the picture since he's the father of their children," the source says. "He isn't threatened by Kourtney and Travis' relationship at this point."
"[Kourtney] doesn't think it will last long and is having so much fun with Travis that it really isn't something she even thinks about," the source says of 37-year-old Scott's relationship with the 19-year-old model. "She knows Amelia is young, pretty and Scott's type, but she doesn't really care."
Scott also seems to see his relationship with Amelia as casual, as one source told ET earlier this week.
"Amelia is so into Scott and they're continuing to have a good time together. Their relationship hasn't necessarily gotten more serious, but they're compatible, get along and he's having fun," the source said. "Scott isn't looking at Amelia as someone that he could settle down with one day."
Meanwhile on Keeping Up With the Kardashians, Kourtney's family is still pushing for her to get back together with the father of her three kids -- and Scott doesn't seem opposed. Check out the moment when he playfully talked about marrying her "right now."