Blessings of the Day!
Kitty needs both some lovin' and some play in order to fill in adventure time that was out doors.
It is also possible to get kitty used to wearing a harness so he can go out in the yard under some sort of control.
We used to do this with Queen Victoria Grey and Calamity Jane Grey. We'd put them in harness, on 25' individual tethers. The anchors were under the bushes, so they could lay in sun or shade. Both kitties were quite bright and quickly learned how to move around and not tangle themselves.
This was never unsupervised by my wife, myself, or both of us, save for a few minutes when people necessities called...we lived on base at the time, so it was a very safe habitat for them.
One time, Anita went in the house for a moment to check dinner, which was in the oven. Likely less than 3 minutes.
Cammie climbed the tree near the front door to the extent of her tether, slipped, was suspended, manged a "Houdini" and was sitting just outside the door waiting to come in; tether swaying in the breeze. =)
Sounds like a win win situation to me. The cat has stopped roaming and thus less likely to get into danger and certainly less likely to impregnate other cats. Is she giving him the attention he is asking for when he follows her and whines? That is not depressive behavior.