I don't normally do straight translations from dude to lady. But this one time I will. When he says "This is going too fast and I want to slow things down," what he is really saying is "I really regret talking about buying a house with you after three months of dating."
The two of you got too serious way too fast. And now he is trying to slow things down. Granted, he is doing it in an awkward way. But his instincts are right on: you both moved too fast. Slow this jam down. For real.
Clearly, the two of you have some chemistry. If you didn't, then you wouldn't be suffering from your current hangover. You both met. You both blushed. Lips smacked. Chests heaved. Hearts burst like baked potatoes. And then one night, naked, you both made promises to each other in the dark. Sometimes, two people can get drunk on words, and dreams and the magical "what if..."
This can all be fun, provided you don't confuse midnight daydreams with bright, shiny reality.
You don't know it, but your guy is being emotionally responsible. It's only been three months. According to you, three great months. Slow things down. Work on a fourth great month.
Perfect advice, perfect!
It's important that you realize that it's only been 3 months. I agree with RP (and your BF), take your time and enjoy your relationship for what it is. Piling more on to it, can cause you to overlook things that you (or your BF) might later regret overlooking.
"Don't confuse midnight daydreams with bright, shiny reality." ~ Brilliant!
Money is the number one factor in divorce these days. Yes, you are not married, but mixing budgets SEVERELY complicates things. Step back a little. Live and learn each other before throwing something that huge into the mix.
Buying a house together is only going to make things more complicated during a time when you are still getting to know each others in's and out's.
Don't forget that in the first three months, both of you were high as kites on Dopamine and Serotonin aka the love chemicals. He probably came down from those chemicals and realized that in reality, you two will need a lot more time together to make a decision like that. Focus on having fun and getting to know each other. Who knows, a home together may be down the line.
"Hearts burst like baked potatoes"
Normally you're dead-on with the sexy similes but this was the most unsexy, yet hilarious mental image I've had in a while.
i totally agree with the advice given and the above comments, THAT could be the reason. However, it has been 3 great months according to HER. I am not saying he wants to dump her or anything, but another possibility for his words could be that he's having second thoughts about the relationship. I think it is entirely possible for one party to have a different view about where things are going in a relationship. I just hope that i am wrong.