I believe the more important question here, is why in the world do you feel responsible for someone you have only known 90 days? 90days that is a drop in the bucket in comparison to the rest of your life. Honestly, you do not truly know this person.
You state that you had an intense and fast start to this situation. That truly is not the definition of a relationship, what you are describing is [lust,nothing more.
I am sure you have heard the only saying, " when something seems to good to be true, it usually is .
I would take a step back and work on me, and figure out why I felt the need to invest my hard earned money on therapy for someone who simply wasn't invested in me.
There are plenty of worthy charities who can put your donated dollar to good work.
You are not responsible for him, he is an adult, he will figure it out or not. Either way, you are free to go and live your healthy life.