What differentiates healthy relationships from toxic ones? Basically, people in healthy relationships have partners who don't necessarily make their lives complete, but complements their lives in just the right way.

To help people identify good relationships from bad ones, marriage experts have shared with The Huffington Post three tell-tale signs that a relationship has turned toxic.

First, couples in toxic relationships no longer feel free to pursue their hobbies and maintain friendships outside of their relationship. Kari Caroll, a couples therapist in Portland, Oregon, said people in mature relationships will realise that they need to get some air from the relationship and pursue outside interests.

"When a partner is too attached to allow you to enjoy something on your own, it can lead to sacrificing one's own identity to appease the relationship," she said. "If your partner has fears about you doing things on your own, it could turn into the self-fulfilling prophecy. In other words, you may ultimately seek even more space and leave."

Another sign is that people act noticeably different with their family and friends when their partner is around. Marie Land, a psychologist in Washington, D.C., said those in healthy relationships don't have to act differently around those they love when their partner tags along.

"If you act differently when your partner is in the room, it's a bad sign," she warned. "You shouldn't feel the need to adjust your behaviour based on your partner's presence."

And lastly, those in toxic relationships find fault in their differences. Whatever these differences might be — whether it be concerning food preferences, or musical choices, or hobbies — these things make people unique. Amy Kipp, a couples and family therapist in San Antonio, said couples' differences actually make the relationship interesting.

"In toxic relationships, couples become enmeshed with each other, and differences are often seen as threats to the relationship," she said. "In healthy relationships, differences in interest or opinion are not only tolerated, but celebrated."