Jillian Michaels and her partner Heidi Rhoades share a home, 15 pets and are parents to 5-year-old daughter Lukensia and 3-year-old son Phoenix. Even though the couple is in a domestic partnership, Rhoades is starting to put the pressure on Michaels to take their relationship to the next level.

In a series of sneak peeks for the Tuesday (March 8) night season finale of Michaels' E! reality TV series "Just Jillian," Rhoades gets emotional while discussing marriage with Michaels, but Michaels doesn't believe in marriage. The former "Biggest Loser" star seeks marriage advice from friend, TV personality Maria Menounos.

"Marriage means something to me and I want it to mean the same thing to you," Rhoades tells Michaels during a dinner date, choking back tears.

"What is the difference between where we're at now and being married?" Michaels asks her partner.

After their emotional discussion, Michaels sits down with Menounos because she can relate. Menounos has been in a 19-year relationship with her partner Keven Undergaro and both women opened up about their fear of marriage.

"It's hard for a partner to understand it, perhaps, especially if that's something that she wants," Menounos tells Michaels. "Because it almost feels like you're denying her, like you're not sure she's the right one."

Michaels explains that it's not that she doesn't think Rhoades is the one for her and she asks Menounos about how her partner Kevin feels about marriage. Menounos says it's different because marriage doesn't matter to Kevin, but now Menounos is starting seriously consider marriage.

"It's not that she's not the one," Michaels says. "I think that to be truthful, and this is gonna sound crazy, I have this - I don't want to say fear. But I feel like I am preparing myself for the day she wakes up and goes, 'I'm done with you.'"

She explains that her partner's personality is more reserved and quiet, and she worries that Rhoades may fall out of love with her without being honest about it until the day she decides to leave. Michaels opens up and says that's been a pattern throughout her life.

"I have to say that I think you could actually play into the self-fulfilling prophecy by not going for it," Menounos advises. "I have a perfect house for a wedding by the way, many people have gotten married in my house. I'll host the wedding, it'll be beautiful."

Watch the clip below and be sure to catch the season finale of "Just Jillian," airing tonight at 10 p.m. on E!