Derek was ecstatic. He was pregnant. He understood that Spencer would be more reserved. They had never really talked about it but Derek assumed that with neither of them being on birth control, there was a silent acceptance. They had stopped using condoms, after health checks, and as they switched positions frequently Derek was excited when he was the one to become pregnant.
For Spencer having children never really occurred to him. He spent his childhood looking after someone why would he want to do it all over again for the rest of his adult life?
Not everyone makes a good parent and being a good parent has no correlation with being a good person. The same is to be said of not wanting children. He always hid behind the idea of genetics and disease, 'I don't want to risk their mental health'.
So when Spencer confronted Derek and he admitted his pregnancy Spencer was stunned. Thoughts whirled around his mind. But this was not the time and place. Seaver had just had puppies and the team were gathered together to celebrate and coo over them. She was embarrassed, she hadn't always felt welcomed in the BAU family and to her this was acceptance.
Spencer wasn't prepared to steal her thunder, besides Derek and he weren't very vocal about their relationship with the rest of the team. They really needed to be alone and talk.
Spencer had played around a fair bit when he was younger. Abandonment issues meant he was never quite ready to settle down. Spencer had fun, he looked after both himself and his partner, it was always safe and consensual. Spencer didn't need to settle down. But Derek changed all that.
It was a slow dance but eventually they ended up in a courtship and together they helped each other and they became a couple were they supported each other. Everyone has their problems and as a couple they worked through them.
Once Derek and Spencer had started experimenting more within their sex life, Spencer suggested a threesome. Derek himself had never had one and when Spencer described a sixsome he had, a 21st birthday gift from Ethan, Derek was intrigued.
Anderson was called in. He was a handsome someone who they both trusted and respected. They used condoms and a good time was had by all.
Spencer drove them home. He gave Ashley a big hug and the puppies a quick pat on the head when they left. Spencer liked driving, it kept his body busy and his mind could think.
Derek was silent. He knew Spencer so he knew that this may not be the happiest of news for him. Derek wasn't sure what to do as Spencer spoke, as he told him the 98% statistics, as he told him about his mother's fear of vaccinations, of teenage mumps, and infertility.
They pulled up outside of Derek's apartment and Spencer struck the final blow. "I don't want to be a father. I don't want something so permanent." Derek stormed off into his home and Spencer left for his. He wasn't welcome at the moment.
It all happened over the phone. Anderson was young and didn't love Derek, but he would like to be part of the child's life and would help in anyway he could. He said that no matter what Derek did or chose Anderson would support him.
Derek broke up with Spencer. They loved each other but neither were willing to compromise. A long term relationship would never work. Derek wanted a large family and ideally with the man he loved. Spencer and Anderson were both there when Derek had his abortion.