His having "incidents/episodes" does not sound too good. Why isn't he spending the time he is talking to these other women with you? It sounds to me like he is looking for something and he will continue to look until he finds it.

His google searches for cameras may be innocent. I search for a number of things that could be suspicious to people. I really am just curious. I spend quite a bit of time trying to understand why people do the dangerous and stupid things they do and will do searches based on these thoughts. On the other hand, he may think he has a need for this equipment.

I would confront him and make it very clear to him that your daughters are off limits. Let him know you will prosecute if he gets any ideas and you will not tolerate him going in that direction. It is OK to be easy going but it is another thing to be a door mat. Stand up for yourself and demand his respect. You may or may not get it but at least you will know where you stand.