Does the emission of fluid upon desiring one's spouse, or remembering them, or seeing certain images necessitate ghusl?

If the water you observe discharging from you is maniy (semen – a thin, yellowish fluid discharged by a woman upon reaching climax or in a wet dream), then you must perform ghusl (definition) (ritual bath). If it is other than that, then ghusl is not required; rather, only washing the affected area of the body and clothing and performing wudu' (ablution) are necessary. You have the choice between patience and seeking reward from Allah, and you will be rewarded for your patience. However, if patience becomes too difficult for you and you fear for yourself, you may seek a divorce and marry someone else to fulfill your legitimate right to satisfy your desires through a lawful contract. There is no sin upon you in doing so, as long as your situation is as you described.