My girlfriend’s sister was wanting to have sex with me and was attempting to seduce me.
Dreams about infidelity or sexual encounters with someone who is not your partner can be unsettling and may leave you feeling guilty or confused. However, it's important to remember that dreams are often symbolic in nature and may not always reflect reality.
In this dream, your girlfriend's sister may represent some sort of feminine energy or quality that you are drawn to. Alternatively, this dream may be related to feelings of guilt or temptation in other areas of your life.
To understand this dream better, you may need to examine your own thoughts and behaviors in waking life. Are there any situations where you feel as though you are being pulled in two different directions or are struggling with choices and temptations? It may also be helpful to talk to your girlfriend about any concerns or doubts you have in your relationship, especially if this dream has left you feeling uneasy.