In an absurd way it sort of makes sense? If you assume he has been going from crisis to crisis and not actually *dealt* with the trauma, but just pushed it aside - that trauma would just burst to the surface, and he would regress to a very young man with no means of actually dealing with any of that.

In that case, him not wanting a relationship is probably the best thing, because clearly he is not ready for it.

He should take pointers from Astarion, who is a badass! Dealing with trauma and overcoming it - I have so much respect for him.