The 47-year-old actor started dating the 39-year-old model last month following his split from wife Megan Fox but she ended things this week because she wanted to settle down and he wasn't ready for a serious relationship, sources told TMZ.
Insiders also claimed that Tina had been getting abuse from fans of Megan, 34, and Brian and ''the bullying was disheartening and really affected her and definitely played a part in the breakup''.
Meanwhile, Brian previously admitted he was ''disappointed'' in Courtney Stodden for sharing a bizarre video of them in a hot tub together, saying it ''kinda sucked'' that she posted a video online after he started seeing Tina, as he said she knew it would ''cause problems''.
He said: ''Courtney, super nice ... but disappointing. I was just trying to be a nice guy, I shot a video for her friend Ashley, saying hello ... That was a month-plus ago, that was back when the pictures of her and I came out.
''I was disappointed [that she posted it] knowing that it would cause problems for Tina - and myself - having three kids, it kinda sucks. I think she's a nice person, I just think she's making some bad choices.''
Meanwhile, Brian and Megan - who is currently dating Machine Gun Kelly, 30 - have vowed to stay good friends for the sake of their three children - Noah, seven, Bodhi, six, and Journey, three.
He said of their split: ''It sucks when life changes and something that you're used to, that you've been doing for 15 years, you try and not get rid of but you change ... I really don't want Megan and I to be at odds ... she's been my best friend for 15 years and I don't want to lose that.''
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