Will sexual dreams and the excretion after that in the month of Ramadhan break the fast?

All perfect praise be to Allah, The Lord of the Worlds. I testify that there is none worthy of worship except Allah, and that Muhammad is His slave and Messenger.

Wet dreams do not affect the fasting even if they lead to ejaculation. Since a person does not have any power to avoid such dreams. It is known that Allah does not charge for those matters that are beyond the ability of the person. Allah Says (what means): {Allah does not charge a soul except [with that within] its capacity.} [Quran 2: 286]

However, deliberate ejaculation is forbidden during fasting whether if it is through masturbation, or touching one's wife, or having sex with her.

Allah knows best.