Having found out that Thompson had fathered a child with another woman after she and her then-boyfriend had conceived their second child is 'a bittersweet situation' for Kardashian, according to a source

Tristan Thompson, the father of Khloé Kardashian's children, is involved in a 'bittersweet situation.' While Kardashian's excitement over her second pregnancy was quickly cool when she found out Thompson had also fathered a child with another woman late last year, news quickly spread that Thompson had also fathered another child via surrogate.

It was bittersweet for Khloé when she found out Tristan's latest cheating was exposed shortly after Khloé learned that her surrogate was pregnant,' a source tells PEOPLE.

A source says Khloé was incredibly disappointed in Tristan, but, as she always does, she turned it around and focused on the good.'

Thompson was revealed to have fathered another child with a woman named Maralee Nichols in December. As Thompson, 31, was dating Kardashian, 38, when the child was conceived, he confirmed he was the father of Theo. He was born on Dec. 1, and Thompson confirmed he was the father in January.

In an Instagram statement, Thompson apologized, 'Khloé, you do not deserve this. You do not deserve the heartache and humiliation that I have caused you.'

He went on to say, 'I am so sorry for the way I have treated you over the years. I certainly have not acted in a way that makes sense with the way I perceive you. My actions do not reflect my view of you. I have the utmost respect and love for you. Again, I am so sorry.'

It's true that Khloe and Tristan are not together any longer, but they will always stay in touch. However, they were together when their surrogate became pregnant.' 

Having watched the Hulu episode about the paternity scandal, Khloé recently commented: 'It's not easy, but I think it's also a form of therapy for me at the same time, and I'm curious to see how my family responds to it.'

It means a lot to me to see those little things, and I like seeing how the whole family comes together - not only in this situation but in any situation - when life is hard.