If bleeding is caused by sickness, your fast is still valid, and you do not have to do anything even if the blood is a large amount, so long as it comes out without you doing anything (to cause it).

If intercourse with your wife takes place using a condom, then ghusl becomes obligatory, your fast is broken and your ihram is nullified. You have to repent to Allah, make up that day, and offer kaffarah.

There are 7 things that will invalidate the fast: 1. Intercourse 2. Masturbation 3. Eating and drinking 4. Anything that is regarded as coming under the same heading as eating and drinking 5. Letting blood by means of cupping and the like 6. Vomiting deliberately 7. Menstruation and nifas

If sexting leads to emission of semen, then the fast is spoiled and he must make up that day. As for expiation, it is not required because the correct scholarly view is that expiation is only required in the case of intercourse during the day in Ramadan. If sexting does not lead to emission of semen, then his fast is valid, and it is sufficient for this person to repent to Allah.

If emission of Maniy (semen) occurred involuntarily, and without pleasure, then it does not break the fast. With regard to Ghusl, the view of the majority of jurists is that it is not required if the Maniy was emitted without desire. Nevertheless, if the person does Ghusl, that will be better and more prudent.