斗得过小三打得过流氓
[dòu dé guò xiăo sān dă dé guò liú máng]
'Fight with a homewrecker and beat off thugs' implies having the grit or ability to fend off rivals in romance ('third wheel' in English context) as well as handle oneself well against troublemakers. This can also indicate someone is brave or has good defensive skills both emotionally or physically.