If my husband masturbates to pictures of a girl he knows and volunteers them..is he developing feelings for her?

Recently I’ve discovered my husband has been exchanging photos with this “friend” of his, she’s sent him semi-explicit photos and he’s sent her pictures of his body and his hard on. (I know this because I’ve gone through his texts).

The thing is that the girl lives in another state. She’s not local and I know it’s not an excuse but it changes the proximity of the situation - I know they have never had sex.

Does he have feelings for her or could be developing feelings for her? They’ve been in contact for almost a year and it seems like the sexting is fairly recent