Is She Really In Love?

I have a friend who lives with her lover (both are lesbian). They share expenses, parenting (one has a child), etc. However, my friend recently lost her wallet due to travel and needed to borrow money for the weekend. She said she didnt want to let her lover know her wallet was lost. I couldnt understand this. If you live together, and do all of the above, in love: why be hesitant in letting your lover know? Also, she says she's in love with her girl, but has a problem being faithful. Just the other evening she shared a conquest she experienced. I don't understand. I have never met a woman who was "in love" but had to cheat. She says she will marry her one day. I am trying to give her the benefit of doubt, but I am struggling to understand this. I dont want to ask because she may get offended. Can someone offer some wisdom?