Don't put yourself down. My husband was married when I met him. One can't know the "status" of another's marriage, what they may be doing with their lives, how they may think of you, until they, themselves say.

If you have to ask yourself whether or not to pursue, it sounds like he isn't working very hard at his pursuit, may be playing it "safe" is having you and his wife and any other "girl friends" he desires.

I think you either need to break off contact with him (for your own sake) or let him know, in no uncertain terms, in person, that you have more than dog walking thoughts of him. It's hard. I still remember when my husband turned to me after everyone had left work, he was my boss, and said, "I have something to say to you" and I thought I was going to be fired

I, myself, would stop dog walking with or talking to him and start new routines. If someone spends time with me, "alone" and doesn't declare themselves "mine" in some way then they don't have the sort of personality and self I'm looking for in friend or lover. My husband was in a marriage and pursued me; I didn't have to worry that he'd get "cold feet" or turn wishy washy on me; as a matter of fact, while still living at home he told his wife he would be dating me and would be moving out as soon as he could and he did all that he said. I was not attached in any way and it was actually me who had the feet dragging problem but he and I realized we had fallen in "fond" rather than love, we took the relationship slowly (he moved into his own apartment, not in with me or me with him; shopped for it himself, established his own identity as a single man and he did not ask me to marry him until after he was completely divorced, over five years later).

Relationships take a certain amount of "evenness" in feeling, respect for self and others, worldview? I don't see anything in what you have told us where this guy is reciprocating on the same wavelength to your feelings and desires. I think going any further on your part might get yourself deeper mired and hurt and being alone in those circumstances aren't fun?