Khloe Kardashian is ''very disappointed'' in Tristan Thompson.

The 34-year-old reality star broke up with the basketball player after he was accused of kissing Jordyn Woods - who is the best friend of Khloe's half-sister Kylie Jenner - at a party last month, and it was recently claimed Tristan hasn't been making an effort to spend time with their 11-month-old tot True in the wake of the break-up.

And now, sources say Khloe continues to be ''saddened'' by Tristan's actions in regard to their tot, as she's still ''bitter'' that he ''isn't trying harder''.

A source told People magazine: ''Just in general, he isn't spending much time with his daughter. It's very upsetting to Khloé. To her, True is the most important person ever. It's very difficult for her to understand how Tristan isn't willing to make more of an effort to spend time with True.

''It saddens her that True doesn't have a very close relationship with Tristan. Khloé has always done everything she can to encourage Tristan to spend time with his daughter.

''Khloé seems bitter about the fact that he isn't trying harder. She just doesn't understand it. It's very disappointing to her.''

Meanwhile, it was claimed the 'Keeping Up with the Kardashians' star thinks Tristan, 28, has ''moved on'', and no longer cares about their family because he isn't making enough of an effort to see True.

Another insider said: ''Khloé is getting extremely upset with Tristan because he isn't really making any effort to be involved in their daughter True's life.

''Khloé understands he is on the road because of basketball and lives in Cleveland, but she just feels that Tristan has moved on. Tristan's attitude seems to be, 'I will see True when I see her.'''

Khloe's concerns come after sources said the former couple were ''on the same page'' when it comes to custody over their daughter.

An insider shared earlier this month: ''Khloe has True for the majority of the time. Khloe's able to bring True or be with her at work, where Tristan can't. Also, True spends a lot of time with her big family and all the cousins are in LA so it makes the most sense for her to stay with Khloe. Khloe and Tristan may have their issues but Khloe will never deny Tristan a chance to spend time with his daughter. Things may change in the future, but for now Khloe and Tristan are on the same page with True being with Khloe for most of the time.''