Sex matters
My girlfriend is acting very strangely. She’s listening to new music and dressing differently. She’s become distant and is spending a lot of money.
More significantly, she’s gone off sex, which is strange as not so long ago she couldn’t keep her hands off me. Could she be having an affair?
Your girlfriend needs to come back down to earth with some honest answers. Clearly something new is going on in her life. Ask for a conversation and make it clear that you’ve noticed changes in her that are setting alarm bells ringing.
Can she tell you what has changed, or do you have to start the undignified process of asking others and digging around? Trust your instincts and don’t allow yourself to be fobbed off.