Dear Roe,
My oldest daughter (24) is pregnant and half living with her boyfriend (26). I recently discovered my younger daughter (18) having sex with her sister’s boyfriend. My older daughter is now back home and my husband is very upset about it. He doesn’t want my younger daughter in the house. I’m in the middle of my two daughters and my husband and trying to help both. I need help.
What an absolute mess. I’m so sorry that you – and your eldest daughter – are going through this.
I admit that if your daughters were the same age, my answer would be different, but I am keeping in mind that your youngest daughter is 18.
Is she old enough to know right and wrong? Of course. Old enough to know that sleeping with her pregnant sister’s boyfriend is wrong? Absolutely. But her ability to understand long-term consequences is not equal to that of a fully grown adult.
A brain’s frontal cortex is responsible for decision-making and understanding consequences, and isn’t fully developed until about 25. So not only is it possible that she made a decision without fully considering the layers of damage it would cause, but there’s also another possibility.
An 18 year old is more vulnerable to manipulation than an adult in their 20s. You don’t say anything about suspecting that your youngest was coerced or manipulated in any way by your eldest daughter’s (hopefully ex-)partner, but if you haven’t already, you need to ask that question.
You may have two daughters who have been harmed by this man, and two daughters who need different types of support.
If this isn’t an issue, and your youngest freely made the decision to sleep with her sister’s boyfriend, you need to have some ongoing conversations with her about what she was thinking, if she fully understands the impact of her actions (that you can explain in full), and if she is ready to acknowledge how much this has impacted her sister’s life.
She is technically an adult who has made a truly awful decision – and now she has another decision to make: is she willing and able to acknowledge the ripple effects of her actions and be accountable?
A family therapist will be able to help you have these conversations in a mediated way – and if your husband and eldest daughter are open to it, it is also a good option for some sessions with the entire family.
As for your eldest daughter, her wellbeing of course needs to be a priority, and anything that will minimise her stress levels is vital due to her pregnancy. You need to ask her what she needs, and how she feels about living with her sister right now.
I don’t think your husband’s idea to not have your youngest daughter in the house right now is necessarily a terrible one, but there is a world of difference between simply kicking a teenager out of the house and arranging for her to stay with a friend or relative for a set amount of time so everyone has some time and space to process and come up with a plan for how to move forward.
Your family has been damaged by the decision of one man and possibly your youngest daughter – but you can collectively make decisions about your next move, and how to hopefully heal.
The best of luck.